Not an actual mouse, just a computer mouse.

I'm doing some computer work for an organization, and they're having a weird problem with one of their servers. About half the time they boot the machine up, when it gets to the login screen, the mouse starts going batsh** crazy. It constantly jumps all over the screen. It even appears that it's clicking, as occasionally it moves the login window around if it lands on the title bar.

The only thing to do is a hard reset of the server, and pray that it doesn't come up the next time it boots. Which seems to be about a 50/50 chance.

So far, I've tried uninstalling and reinstalling the mouse a couple times, and I've even tried disabling the PS/2 ports in the BIOS. Any other suggestions?