There may well still be some Creative references in the Registry, or even ASIO4ALL.
 
You can determine if loaded plugins are causing dropouts and such, by simply hitting the letter 'E' on your computer keyboard, which will toggle 'bypass all effects' on/off.  If you do this to bypass all effects and the dropouts go away, then you have established that one or more of the loaded plugins are at least partially at fault.  If, on the other hand, bypassing all effects does NOT clear up dropouts, then it tells you that something else is at work to cause the dropouts.
 
If you were to carefully go into Regedit, and search for Creative (don't do an exact match), you may locate leftover references to the Creative drivers, but if you find some, you might want to post them here so we could help determine if they could be safely deleted (with a backup/export of the registry done first, or course).
 
Anyways, I think we can get to the bottom of this stuff - hang in there.  :)
 
Bob Bone
 

I am not sure SONAR 5 has a global FX bypass option.
 
Tracks with the archive button enabled are effectively ignored by SONAR so archived tracks should not cause dropouts. Programs running in the background could be an issue. Disk fragmentation may contribute. Running with too small an ASIO buffer or WDM setting may be an issue.

Glad it made an improvement. Sound Blaster PCI cards used to be recommended for audio, can you believe that!  So programs like Sonar wouldn't work properly and then everyone tells you to try asio4all and you end up with an even worse mess.
I speak from my own foray into the world of using a PC for recording back in about 2002. I got so frustrated I returned to using my Atari, Korg and Roland sound modules and an 8 track digital recorder for another 4 years or more.
 
Interestingly Wave Lab seemed to work fine with the Creative Card so I used my PC for mastering and burning CD's only.
When the Atari's monitor died I was forced back to the PC and my copy of Guitar Studio. 
I joined the forum back then.  A bit of reading and a few posts and I saw the light and I bought an M Audio fast track pro. But until I removed the PCI card and did a complete re install of my OS I could not stop the Creative driver from shutting down the M Audio at random.  Dropouts and huge issues with soft synths. 
I also got into buying faster hard drives so a 7400 RPM 250 Gig drive and a fresh install of XP sp3 and Sonar 7 and all worked just fine from then on. And that was on a P4 with 2 Gigs of RAM. 
At least XP is easy to re install and actually a nice fresh install perks things up. ?? Windows updates which I'm not sure they make available anymore. I'm typing on a Windows XP laptop I use for mobile recording. I shut off windows updates 2 years ago. I still have MS Security Essentials and it updates. But make sure you can still get drivers for your computers system and devices. I've run into this a few times with XP. Windows 7 or 8 seem better at installing proper system drivers from scratch. 
 
And a side note that you can update to X3 basic for real cheap these days. But it won't run on XP. 
 
There might be a manual way to completely remove  asio4all and creative in the registry but myself, I found it sometimes quicker to grab my XP sp3 disk. 

scook
I am not sure SONAR 5 has a global FX bypass option.
 
Tracks with the archive button enabled are effectively ignored by SONAR so archived tracks should not cause dropouts. Programs running in the background could be an issue. Disk fragmentation may contribute. Running with too small an ASIO buffer or WDM setting may be an issue.

Ya, I read putting recorded files into a Archive track would reduce, (or eliminate?), the data from being loaded into the RAM, so help preventing maxing-out-the-CPU thus preventing my dropouts.
 
I'd rather not do it, but if it might help, I do it.
 
I'm happy to max all the buffers that might help. There seems to be many buffers listed all over the place. Can you tell what to boost to what? I'll try it.
 

sock monkey
Glad it made an improvement. Sound Blaster PCI cards used to be recommended for audio, can you believe that!  So programs like Sonar wouldn't work properly and then everyone tells you to try asio4all and you end up with an even worse mess.
I speak from my own foray into the world of using a PC for recording back in about 2002. I got so frustrated I returned to using my Atari, Korg and Roland sound modules and an 8 track digital recorder for another 4 years or more.
 
Interestingly Wave Lab seemed to work fine with the Creative Card so I used my PC for mastering and burning CD's only.
When the Atari's monitor died I was forced back to the PC and my copy of Guitar Studio. 
I joined the forum back then.  A bit of reading and a few posts and I saw the light and I bought an M Audio fast track pro. But until I removed the PCI card and did a complete re install of my OS I could not stop the Creative driver from shutting down the M Audio at random.  Dropouts and huge issues with soft synths. 
I also got into buying faster hard drives so a 7400 RPM 250 Gig drive and a fresh install of XP sp3 and Sonar 7 and all worked just fine from then on. And that was on a P4 with 2 Gigs of RAM. 
At least XP is easy to re install and actually a nice fresh install perks things up. ?? Windows updates which I'm not sure they make available anymore. I'm typing on a Windows XP laptop I use for mobile recording. I shut off windows updates 2 years ago. I still have MS Security Essentials and it updates. But make sure you can still get drivers for your computers system and devices. I've run into this a few times with XP. Windows 7 or 8 seem better at installing proper system drivers from scratch. 
 
And a side note that you can update to X3 basic for real cheap these days. But it won't run on XP. 
 
There might be a manual way to completely remove  asio4all and creative in the registry but myself, I found it sometimes quicker to grab my XP sp3 disk.

I think I'll remove my Creative PCI card and hunt down any reg references.
 
I'm happy to reload Windows XP, but I ran into an issue last time I did it. Good time to bring it up: Of course I saved my Sonar folder with all the saved Projects and file data. After I reinstalled XP & Sonar, Sonar will open my old Sonar saved files, but will not PLAY any of my old Project files/clips.  When I try to play, I get the message, "Unable to open audio playback device. Device may not support the current project's audio format or may be in use."
 
My old projects/files are saved 24-bit, and post-XP-reinstall, I do 16-bit recording. Still, I've tried setting all Sonar bit depth settings to 24-bit (Options/GlobalOptions/AudioData/File Bit Depths), close/re-open, open older 24-bit projects, but I still get the same error. That's got me scared I'll not be able to open all my current Sonar files if I reinstall Windows again.

Freezing and archiving will reduce load.
 
Usually the only buffer than needs tuning throughout the life of a project is the ASIO or WDM setting in the Mixing Latency section in Driver Settings. At least, I believe was called Mixing Latency that in SONAR 5. It has been almost 10 years since I worked in SONAR 5. The value will need to change depending on the project. All the other buffers like Playback and Recording I/O are set and forget. These settings are system specific so it is difficult to provide settings to try but once dialed in, these won't need to change.

The word length is not a issue, Sonar works at 32 floating point.   It is the clock rate that gives that warniong. You get that message if your drivers don't support a certain clock rate or if they are hung up while switching.
I used to use 48,   But I wanted to use my old Yamaha 01V mixer and it only runs at 44.1. 
So as a result I have a lot of older projects that run at 48. All that happens is you hear a crackle and a pop when opening the projects as the audio engine switches clock rates.
But I've also had them hang up and get that message. Albums at 48 are all finished but I am re doing all my backing tracks and it's driving me nuts when I open one that is 48.
Anyway if your audio interface supports both 44.1 and 48 the projects will run.
Once again that message is probably something to do with those bad drivers lurking.  
 
What I always do is pull the C drive and put it to one side and use a fresh Hard drive for the re install.  1 TB 7400 Drives are around $50.  That way it's easy to go back if something doesn't work out. .  Just put the old drive back in. If all goes smoothly I either put the old drive on the shelf, put it in a external drive encloser or use it as a data drive inside. 

Sculpt7
When I try to play, I get the message, "Unable to open audio playback device. Device may not support the current project's audio format or may be in use."
 

It has been a while since I used XP, but Windows itself has a designated file format somewhere under preferences in Windows for your Sound Options. I am not sure of SONAR 5, but some programs require the windows setting to match the program settings or they will not talk to each other (i.e., there is no "middle-man" converting the data). This may be why your bit-depth field is greyed out (since SONAR will adapt itself to the audio interface).
 
A couple quick things to check -

1. Look in the sound options for XP, and check the "properties" or "settings." I assume you may be set to "CD quality" (why you are "locked" in to 16bit/44.1KHz). See if you can adjust this to the project parameters.
2. Try running SONAR in WDM mode. Situations also occur where Windows will take ownership of a device on boot. Many ASIO devices are "exclusive," so if Windows owns it, SONAR cannot use it. WDM mode allows multiple audio interfaces to be accessed/shared.

*Dupe*

(Thank you for the clock rate & buffer information!)
 
I'm still getting dropouts. (It's improved, but still dropouts)
 
I have a question on using ONLY my PreSonus driver(s): 
 
When I removed my Creative sound card, and tried using Presonus drivers only, I was not able to record audio originating from my PC (let's say from Youtube). So I reinstalled my motherboard sound drivers (Realtek High Definition Audio Ver 5.10.0.5874, Device Manager: Realtek for Audio Devices, Mixer Devices & Line Input Devices). Then I was able to record youtube in Sonar5.
 
Is it possible to record PC source audio (youtube) with ONLY using my Presonus Firepod & Presonus drivers? If so, what was I doing wrong, or what did I forget?
 
When I only had the Presonus Firepod and Presonus drivers installed (no Realtek), the only thing connecting my PC (youtube source) to my Firepod is the firewire. I could heard PC/youtube audio coming out of my Firepod (headphones), but no matter what I set in Sonar5, I could not get an audio signal in Sonar5. All the drivers in Sonar5 were set to Presonus, but nothing. There's no "Fire Wire" option (in Sonar drivers list) like there is for Firepod in 1&2, Firepod in S/PDIF L.  Sounds like you're telling me it's possible (use presonus ony), so I must be missing something.  (Remember, need to avoid feedback.) Can you advise me?
 
Thank you! Greg
 
http://www.presonus.com/products/FP10