If you have spare memory laying arround, I would try testing it out before formatting your drive and reinstalling everything.... cause if that's all it was, it'd be alot less work.
If you're getting these stop messages while playing music... I would try uninstalling the sound drivers, and reinstalling them. And maybe just for kicks, try moving your sound card to a different pci slot, both before un/re-installing the sound drivers, and after if that doesn't fix the problem. (unless you have like a sound blaster extigy or some other usb sound device).
Those are my thoughts for the moment.