Stickman
Great Info I did'nt know that. I may need that someday, I will make a note.
You know there could be a problem with Hardware or curruption with drivers, program file, or even Sonar or Windows - If this just started happening out of the blue.
As long as the problem is happening to all you Project files you could rule out a corrupted project (as long as you did not save on top of the original currupted project file)
My first step would be a total wipe of the C: drive using a "disk image" backup created when things were OK. This would be the fastest test to rule out Program Curruption and Drivers.
Then we get into a mess when were talking about a hardware issue it could really be any thing Sound Card, Video
Card Mother Board who knows and to be honest I would not want to advise in that case because my knowledge on hardware failures is very limited "$$ Knock on wood"
I hope this helps you for what its worth.
Ps. Make sure you back up all your projects and custom folders/presets or anything you can think of if you choose to wipe your Hard Drive.