I have this very strange problem on one of the PC's on our network whereby the mouse cursor seems to jerk about very slightly and move slowly towards the top left corner of the screen, even when left alone. I'm quite certain that the machine isn't infected with anything as I've run virus scans and a couple of spy/malware scans and all have come up clean and I've made sure there are no processes running in the background that shouldn't be.
I know it's nothing to do with the mouse or the ports (tried USB and PS/2) as it still happens with the mouse completely unplugged... It also continues to happen after a reboot.
Does anyone have any ideas on this as I'm stumped and the user is getting rather frustrated with it.