Thanks, zigzag. The problem does not occur in safe mode, so you're probably right that it's a driver conflict.
Thanks, greg, especially for pointing me to all those Win7 resources I didn't know about. It will take me awhile to sort through them all, but one thing I noticed from the System health report is that one of my device drivers isn't installed. Drilling down, there's a PlugAndPlay Device Configured Fail Count. Is there a way to determine which device is the offender without unplugging everything one-by-one (I've got a lot of USB devices).
Also, I understand your comment about uninstalling the display driver and letting Windows reinstall it, but can you elaborate on the rest, though ("uninstall the device driver software along with it ...")?
Thanks again, both of you.