mouse problems

The driver could be corrupted. You can uninstall and reinstall and see if that fixes it. I have seen it happen.

Have you uninstalled the Driver's and reinstalled them? Also what kind of mouse is it? Is it a optical mouse, USB, or PS2?

If uninstalling/reinstalling doesnt help, try a different port.
Also, USB mice can stop functioning if a lot of 'noise' is around. I had someone near a shredder (not used often), but every time the shredder was used, his mouse would not work. If there is a lot of 'noise' around, try moving some things around a bit.
Reboot, this will fix some problems (especially if it is PS2)
if they fail, try the mouse in another system, or replace the mouse (optical or laser are best).

Have you gone into the control panel and tried adjusting the mouse settings? If its a USB mouse unplug it while the computers running and pug it back in, and try shutting down the computer remove the mouse reboot and plug it back in.
It could be that the mouse has gone bad try another to see if dose the same thing.

If you have a USB Mouse MS suggests that you turn off the computer unplug it for at least 30 seconds and then plug back in and restart, this is supposed to cure USB problems though for the life of me I don't know why but it does work.

Col

installed new mouse,old mouse died thanks everyone

umm you might have gotten the security patch (KB908531) that was glitchy. make sure you get the re-released version of the patch.