mmmmmm have you run virus scans?? that doesn't sound good.
After virus scans you should run sfc /scannow (start > run > type in sfc /scannow) note the space between sfc and the / if not typed correctly it won't run. This is a system file checker that will replace corrupt Windows system files, have your XP cd handy in case it is needed
i ran virus scan, got nothing.. then i ran the sfc /scannow, and it finished, still nothing in my device manager. I am going to reinstall windows tomorrow, just so everything is back to normal.