Recurring PC hang-up, no BSOD, audio loops. "Fixed" before, comes back  

spunk said:

If everything works in Safe Mode and a Clean Boot, then it is a software issue. One of the disabled services or startup items is causing the issue.
It may very well be your video driver. Try updating the Drivers then slowly add one item at a time till it hangs

Gotcha.

One thing I came across in poking around—my GPU thinks that my Shift program is a game. Namely, Need For Speed: Shift. (I've never played NFS on this rig, it's not in my Steam library, etc.)

Other people with a similar problem in NVIDIA forums said that reinstalling the driver helped, so since that's on my list I'll give it a go. I wonder if something like this could be at least one source of bamboozling the video driver.