I'm... baffled.
Mouse problems occurred *immediately* after format/XP Install. So I took out all my PCI cards, replaced the video card with an old Geforce2, disconnected my CD drives and floppy drive, and tried it like that with one of my RAM chips taken out, tried this with each chip in each slot.
Same 'ol same 'ol.
The MX500 works fine in other computers, w/same mousepad. Freezes constantly on mine.
Funny thing is, I have an old PS/2 only ball mouse here I forgot about, and its working fine and not freezing here. Problem is, its a crappy 3 button uncomfortable piece of doodoo. Argh.
Absolutely baffling.