Up until a week ago, playback was flawless. This just seemed to come out of nowhere, DVDs and divx movies play with constant skipping. Checked the venerable "PIO" fall back settings, and everything is running fine. Any help would be appreciated, I just bought a 21" widescreen LCD and i can't even use it now

I also noticed there is slight harddrive activity every few seconds when my computer is just idle, but task manager reveals nothing is running, and system idle is at 99. My CPU usage, however, seems to jump between 3% & 27% for no apparent reason. Scaned for viruses and all that good stuff too, and nothing.

Specs

Pentium M 1.73 Ghz
512 Mb DDR
ATI Mobility Radeon 9600
40 GB HD