There are many reasons why a mouse might just stop working and many
ways in which one might get the mouse working again. Most of the
causes are do to something the user did to, or with, the system.
Causes include: System installs (Roolback to previous versions. Will
deactivate recently installed devices), viruses (Antivirus.com),
spyware system conflicts (Lavasoft Adware 6.0), PS mouse conflicts
(Try OS update/patches, or serial mouse). Worse case the problem is
cause by hardware failure, or simple driver issues. Get the newest
driver, UNINSTALL old drivers and RESTART, then install new drivers.
Good luck, keep me posted. Rob