Hey, I started a new topic over here http://forum.cakewalk.com/FindPost/3582009 to discuss the WASAPI / ASIO4ALL stuff.  I think we hijacked the OP's issue ...

Thanks for all the input guys.
 
It seems that my output was indeed the issue. I just set up a new Focusrite interface, and the projects that I assumed were corrupted are now loading and playing normally again! If I continue to have the same degradation I'll know I have other issues, but as of right now, smiles all around.
 
I'm in the process of building my first DAW, and kept putting off buying the interface in lieu of other components and plugins. Didn't feel a sense of urgency since my stock sound card and ASIO4All seemed to be doing the job well enough. I didn't realize the output could give Sonar such conniptions. Plus, everything sounds better now. Should have done it sooner.

The audio driver is the heart of a DAW system. 
You can certainly get by sometimes with on board audio for simple projects but to use Sonar properly you really need the ASIO driver. 
 
After this thread and the onne started by Abacab I downloaded and installed asio4all and have been using it on this laptop for a week or so. No problems so far, and it certainly brought the loop back latency under control. SO I will now shut up about asio4all. As long as your just messing with midi files and stay out of plug in land seems to work fine.