Sorry but I shall paste the other questions again...
 
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? (I'm checking how you did it).
Anything at all in in the event viewer?
Maybe a screenshot of mix control would be nice.
 
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/ (beta drivers!)
 
>BIOS update for your motherboard?
Possibly, I'll look but the machine is really new.
 
Please do. thanks.
 
And here is how to turn off Intel Speedstep for I7 (I think, I just did a google):
http://answers.yahoo.com/question/index?qid=20100308130827AA18AEG
 
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.
 
Without trying the above first or pasting any errors??
Focusrite normally take two working days to respond via email, however I strongly recommend you take heed of this so you can rule everything out first (don't jump the gun, if anything this will be good for your future interface if you believe there is a fault).
 
You'll need to put in the time, so when you get a chance...
 
Cheers.

• 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? (I'm checking how you did it).
• Anything at all in in the event viewer?
• Maybe a screenshot of mix control would be nice.

 
All done.
 
I can't post a screenshot of mix control because the machine isn't here. There are always things in Event Viewer but they're unrelated.
 
>take heed of this so you can rule everything out first 
I will and I do - up to a point. You have about as many years in computers as I do and as you know, you develop an instinct. A totally unintelligible sound will not be fixed by getting rid of the drop shadow under my cursor! 
 
 
 

As you probably already know , troubleshooting is a process of elimination. And the fastest way to the solution is a substitution of components. 
It is looking more and more like the interface to me. 
So you say you can't get your hands on an other interface, how about another computer? 

Johnny:
>It is looking more and more like the interface to me. 
I'm leaning that way too. I know someone with the identical unit so I'll get hold of it and plug it in. If one that's known to work doesn't work, I'll be happier about chasing problems on the machine.
 
Incidentally, a Focusrite support dude mentioned that other people are having this problem so a solution might not be far away. I'm also going to get in touch with HP, maybe they've solved this issue for other people too.

I got it going! In an act of desperation I thought was sure to be futile, I reinstalled the latest Mix Control and the latest driver and everything came good. I have no idea why, they were there already.
 
I began undoing all the suggested tweaks I'd made to the machine one by one, enabling everything I'd disabled and nothing changed, the Focusrite still worked flawlessly. No problems with throughput or latency. Baffling...
 
I'm overjoyed that I can finally work with Sonar and the money wasn't wasted on the machine or the interface.
 
Thanks to all of you who chimed in on this post, I just wish I had a satisfactory answer as to why.
 
rev
 
 

Yup So it was clearly  the focusrite drivers. Great news. Cheers.

>Yup so it was clearly the focusrite drivers.
Kinda. I can't figure out why though.

I sucks in a way when all of a sudden it all works and there is no clear answer to what was wrong. Might be a case of all the ducks had to be in a row before the drivers were installed. 
Sometimes there's a sequence to installing all this stuff and getting it to talk to each other. 
 
Main thing is you can now get at it and start recording. have fun and may your next 3 years be trouble free. 

>and may your next 3 years be trouble free. 
A nice thought dude - thanks for that. Yes, I wish I knew what the problem was but I'm happy it's gone.

I am suffering the same problems since upgrading to Sonar X3c, crackling and popping on the audio, also the track drops out during playback, I am using a Native Instruments Komplete Audio 6 which worked very well with Sonar X1, but has had problems with X2 and now severe problems with X3c.
I also run Ableton Live 9.1 and do not have the same problems, I am contemplating dumping Sonar because there are just too many glitches in the software that they release and I am sick and tired of being used to beta test programs.