Because I appreciate hearing updates of solutions other post, I will post my own -- at least interim report.   After two days of mucking around with Windows 7 services, applications, and drivers, I finally have been able to resume recording using Sonar LE without the dreaded "Dropout" notice in the lower notification bar.   I do not know to this day night before last I was able to record for an hour without difficulty and then suddenly the next morning and for two days thereafter I was unable to record more than 5-30 seconds without a dropout!   Here's what seems to be working for now (a bit awkward, but tolerable for non-real time use):
 
1) Disconnected LAN cable and turned off Microsoft Security Essentials (real time antivirus and antimalware -- I think this was probably the biggest part of the hard drive churning I experienced).
2) Turned off Windows Search (Searchprotocolhost.exe was taking up a lot of resources - perhaps indexing every file -- I think in either System Configuration utility or services.msc)  This disabled Windows OneNote instant search and I think also the File Explorer "search" bar.
3) Disabled more hidden wireless functions (including Lenovo Access Connections and Profiles - all are related to wireless - this did not seem to improve things, but I don't use wireless at home anyway - I'll worry about travel later)
4) Religiously closed EVERYTHING else on computer - especially Firefox browser
5)  Gave up completely on ASIO drivers for my UA-25EX even at 44.1k sample rate.  Could not get Sonar LE to record more than 5 seconds with them installed, even at the safest settings.   Also failed with WASAPI mode.  Instead, used  WDM/KS driver mode tied to my USB sound card and set Mixing Latency at 10 buffers each maxed out to 347.2 msc (effect latency at 44khz 3124.9msec) and left file system buffers at default 256kb I/O playback and record size with audio driver bit depth of 24.   I have not had a single dropout since.
 
Now for a personal comment:   I read someone online that audio computer users are 'bottom feeders' and must be satisfied with the situation 'as is'.  I could not disagree more.  It is frankly ridiculous that in this year, 2013, with a i3 CPU (2 processors, 4 hyperthreads), on a machine that can easily reconstruct an MP4 full screen video in real time with excellent audio to boot, that it is SO DIFFICULT to simply record audio or play it back in something approaching real time!   3 seconds of effective latency is bizarre and ridiculous.  
 
I know Windows is not a 'real time' time Operating System, but is it so dang difficult to design an operating system that IS real time, or at least can allow user to easily and temporarily and safely give exclusive control a single application like Sonar (working together with a USB sound card?)
 
I have used computers since the Atari days with Dr. T Midi software (1988 to be exact), and I keep dipping my toes back into the water hoping against hope that someone has solved this seemingly insoluble problem:  Real time Audio.   If we can do 3D game graphic rendering in real time at 60 fps, why can't we render simple audio streams on a much lower powered computer?  
 
And my final comment for those who say "have a dedicated i7",   computers are multifunction devices and should be designed that way.  I should not have to completely mutilate my system configuration beyond recognition (and frankly, now it is beyond system restore capability) just to use one application.
 
I don't think I am alone in thinking this as googling the internet for the last two days found plenty of issues with the 'lower' power laptops (which incidentally would have been considered nearly super computers 20 years ago).
 
Rant over, but two days of time wasted is a bit rich for me and it will probably be a while before I do much more with audio on Windows at least!  

My wife has a Lenovo i5. Windows 7 pro 64 bit, 6 gigs of RAM. 7200 RPM drive.  My old Acer died and I had to borrow it to do a live recording session. It is her work computer and set up by the IT guy for remote access of the dental office management software and email. She uses it from home etc. So I was not about to tweak any settings or shut off processes. I ran DPCLAT and it was down in the green , no spikes...I was impressed, this should not be , WiFi was on, MS security and all sorts of remote stuff,, I installed Sonar 8.5 and my Tascam drivers and recorded 3 hours of 8 track @ 24/48.
So I find it amazing that you are having so much trouble with a very similar computer.  
 
I do know that having a nice clean 7200 RPM hard drive is very important for audio recording. 
I'm glad you brought your down to 70 gigs free as I was going to say that was your problem. 
One thing is you seem to have a lot of stuff installed and I don't recommend that. My wifes machine ( and my desktop DAW) has very little installed. The IT guy likes it that way and he probably did the correct performance tweaks. 
 
Window 7 pro is probably a better OS for a DAW too. 

I'm very happy for you, Cactus Music.  I'm glad your wife's work computer i5 with 7200 RPM drive could record live audio and run Sonar 8.5.  However, that does not really help me.
 
>>One thing is you seem to have a lot of stuff installed and I don't recommend that.
 
Why not?  Because software designers are hopelessly wasteful or greedy in using resources?   Why should I have to pay for their laziness?  Why do I need to buy a dedicated computer for every potential application?  That is not only financially and ecologically unfeasible, it is also inconvenient.  The whole point of a programmable computer is to allow one piece of hardware to do multiple things depending on what the user tells it to do.   It would also be very inconvenient to have separate computers for each type of application.   
 
This is a software design problem, not a hardware problem.  There is no reason that OS's and applications could not be designed to play nice (in other words, go into hibernation when not needed).
 
Obviously what we have is an operating system design failure.   Not a hardware problem, it's a software problem.   My point was that an i3 M390  dual processor 2.67Ghz with 8Gb ram (7.8 usable) and 64 bit Windows 7 pro OS and an external UA-25SX sound card doing all the processing SHOULD be able to manage a simple audio record session with elbow room to spare.   5400 RPM drive MIGHT be an issue if I were doing video, multitrack with lots of cuts, or something, but NOT audio. Just count the cycles per second and weep. 
 
There is no way for me to determine with any degree of confidence in a reasonable amount of time (I do have a life) wherein the problem lay, but after disabling Windows Search completely, turning off MSE completely, disabling my (wired!) LAN, AND monkeying around with the USB sound card drivers and cranking the latency up to the vicinity of 3 seconds, I WAS able to complete the recording of an full audio book with absolutely no dropouts.  Wow!  What an accomplishment!  I hope the laptop was having a background process withdrawal attack!
 
I guess my real beef is that computers used to do one thing at a time.  I know it is nice to have lots of stuff going on in the background when we are just browsing the web or doing email, but it is a waste of computing resources and a complete design failure that they do not allow us the option to easily shut everything off and effectively turn the entire resources of the powerhouse in our lap to what the user chooses.   I'm sick and tired of computers trying to think they know best and not giving the user a user-friendly way of choosing to promote or veto extraneous housekeeping (like indexing the drives, networking, or sending backup copies to the NSA).   ;-)
 
It seems a shame to me that the awesome powers of our CPU's should not have a real time capability option.   Reading up on this over the last week has convinced me it is still VERY non-user friendly, but may be possible by completely re-jiggering one's OS.
 
My point was that an i3 with 5400 drives SHOULD be able to manage 2 tracks (actually single mono track!) recording without Sonar 8.5 screeching to a DropOut halt without gutting and reconfiguring.
 
 

Yes, but if there ARE background apps hogging your CPU then audio will possibly drop out. For the last 13 years or more this is all very well documented in every audio recording forum on the net. Computers were not really built with recording audio in mind so we as technicians DO need to make modifications to allow un-interrupted audio streaming. That is why I was initially impressed that my wife's laptop worked so well without my intervention. But it was certainly not stock set up and a competent tech had removed the bloatware etc. 
 
Some laptops are hopeless because of possible conflicting configurations. My son bought a higher end $1,600 Dell laptop that you could not stop the red spikes. Long story but he had to give up, can't get your money back because technically a red DPCLAT spike is not on the radar of Dells support team. As far as anyone could tell it was somewhere in the BIOS and not to be disabled. He even installed both Ubuntu ( Linux) and Mac OS 10? in different  partitions. Same results. He is very advanced in understanding this stuff being a marine instrumentation tech.  
So the spikes can be BIOS related and absolutely nothing to do with your OS or DAW software. Certain combinations of hardware just seem to cause havoc. 
 
I highly recommend Wave Lab 7 elements for the work you are doing. 

I couldn't get rid of the Red Spikes either.  But by disabling (supposedly non-active) stuff (including wireless lan driver and Windows Search) as well as increasing CW latency I was able to record an entire book in flawless mono!    The theory that somehow the BIOS is to blame makes some sense, although I have a hard time imagining there could possibly be that much BIOS overhead - at least accidentally -- perhaps the BIOS maker's intentionally cripple the time responsiveness of the BIOS to prevent our laptops from competing with whatever it is that professional audio workstations use.

However I am not quite willing to concede defeat to computer hardware manufacturers.   Audio visual is HUGE on personal computers (why else would we have 16:9 wide laptop screens when a vertical orientation would be MUCH better for reading PDF's?) but somehow, no one in the music world seems to be complaining loudly enough for the laptop manufacturers to hear.
 
I am not surprised your son had problems iwth Ubuntu, which I consider another bloated OS.  He might try 64 Studio or perhaps Puppy Linux, far more responsive in my experience, and 64 Studio is set up for audio from the start, although it has some limitations for general usage.  I did not install it on this laptop because I dislike the idea of having to devote an entire, multi-purpose computing machine to one application.
 
Bottom line a dual 2.67 Gigahertz CPU laptop (Gigahertz:  A unit of frequency equal to one billion (10⁹) hertz. Also called gigacycle.*)  should be major overkill for recording only 44.1khz audio especially when the DAC is an external sound card doing all the heavy lifting!  (Kilohertz:  A unit of frequency equal to 1,000 hertz.)**   All the CPU is really having to do is paint the GUI screen and channel the resulting stream of bits to the proper hard drive sectors!   What could the OS (or BIOS as you state) be possibly doing that requires so much attention and is not easily turned off with a single switch?
 
* thefreedictionary.com / gigahertz
** thefreedictionary.com / kilohertz
 
 

Of course I cannot answer that with any insight beyond my own personal experiences. 
 
Beside my wife's, I have used 2 old laptops both from 2004 vintage with 1.5 Gigs of RAM and around 1.5 Ghz Processor ( single).They have(had) 7200 RPM drives  I have recorded hours and hours both 2 track to wave lab and up to 14 tracks to Sonar. This is XP SP3 32 bit.
The DPCLAT was way out of line on them. These laptops both had only basic software like Word and Photoshop and you are correct, this stuff doesn't matter unless it is set to auto update itself. Easy to stop all those type of processes in "msconfig"  
But what I found was really only 2 things made the big difference, Wireless card and battery management. 
 
 
My son only tried the other OS systems to experiment with why he was getting the spikes and therefore dropouts and issues with audio recording. He was exactly where you are at.  He deleted them after the experiment failed.
He eventually gave up and he bought a basic Acer laptop for $600 that has worked without issues since. He took DPCLAT on a USB stick to Future shop and they let him run it on a few machines he was looking at.
What he found with most laptops was that just disabling the wireless card would put it in a steady low green. 

I take it you are using Windows 7? Well, if you are, then turn off all the automatic stuff Windows 7 does.
Schedules for defrag, updating Windows, anything and everything. Set Power to always on, and anything else you may find in Control Panel.
 
Windows is always set up for general computing, for recording or using it as a DAW, you have to tweak Windows to perform and not do what it wants to.
 
I guess I can not explain it all, and it will take some time to thoroughly go through Control Panel and turn off automatic things it does, and thoroughly check out your computer.
 
I have a ACPI x64 computer, and the drivers are from Microsoft, if you have manufacturer's drivers (which does not seem like it should be) then perhaps there are updates for your computer. I don't use Wi-fi and it should be disabled in Device Manager - Right click on Computer and then get up Device Manager or find it in Control Panel. It can be Re-enabled when you want to use it. I do it all the time and in the Local Areal Connection made a Desktop icon link so I turn it off or on (Disable or Enable) when I want to use the Internet. Otherwise it is off. I don't use Wi-fi at all and even took it out of my computer I use cable so I never use Wi-fi. Perhaps you do, perhaps it can be disabled and reenabled like I do for my Internet Connection.
 
If nothing else there are articles on the Internet for tweaking a Windows 7 OS computer for audio recording probably, but I went through the computer myself and found out all Windows 7 does. It does this because most people using a computer do not know what they are doing.
 
http://s4-us3.startpage.com/do/search?cmd=process_search&pid=49dcb964aae1d19dada2683b3bc356d4&nossl=1
 
The main bottom line is if you have not set up the computer, then set it up to record with on audio.
It is not set up, until you do that, because most people do not use a computer for that anyway, so Microsoft in their infinite wisdom set it up for general purpose computing and for people who do not know what they are doing on a computer except to run a program or work a job where someone else sets it up in a Office but at home you have to do that yourself or find out how to do it.
 
Of course then you will have to do some things like defragging the harddrive and updating anti-virus programs and Windows Defender (probably on your computer) and Updating Windows on your own and not allow it to be done automatically. Of course if your Internet connection is off, then it can not do that until you are connected again.
 
If bad device drivers, or anything like that, perhaps there is an update for your computer from the manufacturer - I got one for Intel Chip that controls something to do with the Internet - downloaded the program and ran it, and now my computer is updated. I just looked it was Intel Network Connections update program from Intel.
 
Anything that runs in the background can be turned-off, including starting up the computer start programs in Administrative Tools -> System Configuration - (you know that microsoft started that up with trying to make their programs like Office seem to start faster because there is always a little start-up program running when you load up the OS and start your computer. Now, everyone does it, with automatic program update little program or something else that does not need to start up when you start your computer. That is what System Configuration is for - run your computer the way you want to - but do not turn off things that need to run - well it may take awhile to try some things. Like Adobe Update program for Adobe Reader perhaps on your computer - it does not need to run at start-up of your computer - if those programs you feel are interferring then you may want to have Windows not run them when your computer starts up.
 
Well, babbled on long enough, but everything in Control Panel icons should be looked at and set for maximum performance so your computer runs the way you want it to.
 
There is also "verifier" on your computer since Windows 2K. It checks (but usually only for crashes) your drivers to see if a driver is causing a problem on your computer. If nothing else you can put in the driver you wish to check.
Just click START - and in Search (which use to be run but just searching now) then type verifier -and start up the program if you want to see what it does.
 
A lot can be looked up on the Internet in probably several places to tweak your computer and then that will be that.
 
Audio does not take as much as video but still, the computer is not really set up for it.
 
 

Thanks for that (helpful post), I am sure that sometimes if I slow down the post I make may make a little more sense.
It kind of does do that, but actually everything in the computer and looking at it and all of that from Power always being on to USB ports not powered down is somewhere in that OS. Just finding everything may be sort of a problem, but then I hope I am done finding out this stuff on the computer like Windows OS's.
 
http://www.sevenforums.com/bsod-help-support/210693-appcrash-exception-code-c0000005.html
 
Should work for about any error code in windows, perhaps been playing some computer games and graphics card drivers are crashing and stuff with other people's computers, but good to know what can be done in Windows OS's when something happens.
 
May not give all the answers either with Windows programs in that OS, but then usually something will be on the Internet for it.
Like Exception code up there 0X00000005 a generic general error message that means just about anything, but still video drivers (like in a game) can crash the computer to desktop out of the program, and lately it is not the program but the graphics drivers say like from Nvidia and using earlier graphics card from them - in other words there newer drivers do not work with slightly older cards and a lot of players (of games) are complaining.
 
Oh, well that is computers. A mind-headache experience sometimes.
 
Oh, ya, the official microsoft weblink of the link above given in the article forum.
http://support.microsoft.com/kb/244617
 
Yikes, I have to do what - just some little bit of humor.
 
 
 
 

Thanks Spacealf and Cactusmusic.   Very useful info, much of which I have already done but a few new ideas.  All will be helpful to other readers as well.  Spacealf, I was not able to use the link you posted (even manually copying and pasting) although the Search engine looked interesting, it did not seem to find anything useful with the Process_search term(s).    But it did inspire me to further Google searches.  Previous to posting here, I had already spent over 8 hours cumulative searching and tweaking of my system (in addition to disabling Windows search and Lenovo wireless, I also disabled MSE (Microsoft Security Essentials) after pulling the LAN cable and disabling wireless (the latter is harder that it should be for Lenovo - simply turning it off using keyboard shortcuts and so on did not work, I actually physically uninstalled the software, something I hope I do not regret).   I did not have Windows Defender installed (it has been included with and superceded by MSE).
 
I DID find a very useful comprehensive DAW Windows 7 setup guide from Prosonus here (remove the spaces around the '/', I inserted them to defeat the auto-removal of URL links):
 
presonus.com / community / Learn / Optimizing-Windows-Vista-and-Windows-7-for-Music-Production
 
The shear complexity of defeating Microsoft (or other OS) busy-body background tasks points out a huge gap in the OS ecosystem that I think someone will eventually fill.   It simply is not sustainable that people should be forced to make so many relatively semi-permanent changes to a multi-purpose calculating machine simply for one application (audio recording).   Perhaps everyone here can afford the money and space for a 'one-laptop-per-application' ecosystem, but I cannot.  And there is no theoretical reason why an operating system should not be designed to allow "one-click" custom configurations that turn off everything not needed for music making, then allow simple reenabling.  As it is, I will eventually forget to reenable MSE prior to plugging in the LAN cable or make some other simple and avoidable human error.     This is a process design problem, not a technological limitation problem, and if MS (or some other OS maker) wants to gain a major market share in the field of amateur or semi-professional creatives, this would be a fairly good place to start.  Of course, left to corporate wonks, they would probably price such an OS feature out of the range of must of us creatives, so that's why it hasn't happened, just saying.
 
Meanwhile, I already disabled most auto-startup stuff, Aero, indexing, MSE, Wireless, unplugged unneeded USB drives, and so on.   That allowed me to record an entire audio book (monophonic).  When I next have a day to blow I will go through the comprehensive process described in the link above to further optimize for audio.    If this makes my computer unusable for normal things, the changes will not last long though I fear.

@Cactus Music - I am surprised your son was able to connect USB cards to computers at the store -- that sounds like a perfect way to insert malware into computers before they are even sold and a reminder that what you buy at a store may not be 'virgin' territory.   Wipe and reinstall?  Hard with no CD.
 
@SpaceAlf - was your second post intended for this thread?   I somehow missed the connection to this subject (Crashing to desktop?  Maybe I missed something...)