OK, I've managed to get rid of all red bars in the latency tester. But no change. 
 
The High Def driver that comes with the laptop almost works, there's crackling and you don't hear the data on time but at least it can be heard.
 
The Scarlett driver is unchanged. The notes are indistinguishable sounds like a spring being tweaked underwater and it plays the track in slow motion. What next?

OK so please check your windows event viewer for any issues.

.... and please run Windows Update several times. 
 
Also run this:
http://forum.cakewalk.com/Driver-Boost-m2928792.aspx
 
And try disabling Intel Speedstep in your BIOS if the above does not fix it.
 
We assume you are running the latest focusrite software.
 
Also run chkdsk and defrag.
 
There's probably a couple of other options but this is enough to try for the moment.
 
Cheers...
 
 

Scary looking web site, I'd think twice about that. Good way to instal all sorts of malware etc.
 
Revnice, don't get to carried away with every suggestion for OS tweaks. Asking for advice on the internet is a 50/50 crap shoot for receiving the correct solutions. Sounds like your laptop is up to it now anyways.
If you got rid of the DPC spikes then that is not the problem. It's a good starting point for sure.
Good news is your laptop will work perfectly fine once you sort out the driver issue.
I would see if you can borrow another brand of interface to test what's up with the drivers.
And I hope your not actually using your on board card at all, get rid of any traces of it in Sonar.
It's drivers could be interfering with the Scarlet drivers. I would disable the on board audio card drivers and see what happens. It's easy to toggle it on and off.
 

>don't get to carried away with every suggestion for OS tweaks.
Believe me, I'm not, advice on the internet is taken with 20 years of experience. The only thing I haven't done yet is disable Speed Step because the machine is in a different place.
 
I think you're right about testing with another brand of interface. 
 
 

> Scary looking web site, I'd think twice about that. Good way to instal all sorts of malware etc.
 
Standard response, sort of getting bored of it. Sorry you are wrong, I understand where you are coming from but you are wrong it is not crapware. It's actually the best driver update facility I've found, I have tested it, it has helped loads of others. Just be careful how you install it. If you haven't installed and tested it fully like I have (and others) then please don't pass judgement.
 
> Revnice, don't get to carried away with every suggestion for OS tweaks. Asking for advice on the internet is a 50/50 crap shoot for receiving the correct solutions.
 
Thanks for that Cactus I shall remember that (I find that extremely rude to be honest as that comment is clearly directed towards me). Disabling speedstep actually worked for me with my saffire Pro 40 when I had a very similar issue, and this has resolved many other peoples issues with symptoms (regardless of interface).


BTW these are not OS tweaks (I'm not asking to go into the registry or disabling services), this is changing a BIOS setting and updating drivers, sensible for this scenario.
 
P.S. Another thing to try is disabling the high def driver (device manager) and any onboard audio in the BIOS. If you are running antivirus please temporally disable it. Running windows update is always recommended. And (really important) have you checked windows event viewer recently?
 
P.P.S. (unrelated to post I apologise) my degree is in computer science and I've been around PC's since the very early 1990s and home computers since 1980. I'd bang on about my broad scope of high and low end IT jobs but as you know the internet is a 50/50 crap shoot and I know you don't give a monkeys where I'm coming from (personally I can't stand people who bang on about their own credentials or other peoples, or pass judgement upon hunch rather than actual investigation). All you need to know is that I have a track record in the forums (mainly the Sonar X series) and I tend to respect people first rather than dismiss them, so maybe try again, I will (clean sheet)....

Al:
 
The story so far:

• I ran dpclat and by disabling stuff I was able to get all the bars in the low green.
• I disabled the onboard sound 
• I updated all the system drivers with Driver Booster
• I installed the latest Focusrite driver 
• I tried the driver in ASIO and WDM mode and with wavs and mp3s. 

I am no closer than when I started.
 
I'm not talking about a dropout, clicks, glitches, or stuttering. I'm talking about totally unintelligible sound. I could play Back in Black for you and you'd have absolutely no idea what song was playing. The sound is garbled beyond recognition and that's got to be a driver issue.
 
 

Did you run windows update several times (there have been several USB fixes for instance)?
I also suggest you install the optional performance fixes in windows update.
You said you disabled onboard sound - in the BIOS?
Disable intel speedstep in the BIOS just for fun I suggest anyway.
See if you can pull out all USB devices other than you keyboard and mouse (heck maybe even pull out the keyboard and mouse when playing and put them back in). See if you can hear Angus screeching his head off.

Any later drivers here to try (what version of mix control are you running?) NB stick to ASIO mode.
http://beta.focusrite.com/releases/scarlett_mixcontrol/

Anything at all in in the event viewer?
Maybe a screenshot of mix control would be nice.
 
Last thing to try, driver Booster should have updated your motherboard chipset drivers (I hope), but I'm wondering if there is a BIOS update for your motherboard?
 
Focusrite support are brilliant BTW, might be worth sending an email so you can get on their call logging. You might want to point them to this thread, maybe even do a non indexed YouTube vid (you don't have to, just an idea). I notice they've even be posting here but you will probably need to log an issue with them once all this is exhausted.
 
Any other ideas Johnny (don't worry we are friends now, apols for coming down so hard)..
 
Cheers...

Hey Alex, no I'm sorry I came across that way, I was just very leery of that site but I'll take your word all is good... This is a tough one and at this point I'm still thinking the interface it self might be toast. It does happen. I had a Fast Track Pro that never worked properly and nobody else had the issues I had. I wasted a whole year thinking it was my crappy computer. 

No probs I've been the same with other people myself I apologise for reacting.

Johnny:
 
>I'm still thinking the interface it self might be toast.
Now we're talking, my Scarlett is a refurb. I took a chance on it because of budget and the fact that it came with full warranty. I believe the Scarlett and its driver work for other people so it's natural to look into problems with the computer but a bad unit is still a possibility. 
 
Al:
>BIOS update for your motherboard?
Possibly, I'll look but the machine is really new.
 
>Focusrite support are brilliant
I hope so - I have logged the issue with them but they're slow, probably because of the holidays.
 
>pull out all USB devices / disable SpeedStep 
Nothing else is connected, I couldn't find SpeedStep in the BIOS 
 
>Driver Booster 
DB claims all drivers are now 'Perfect'
 
Geographically, I'm two months from everywhere so it's going to be difficult to substitute the Scarlett but I think that has to be next.