Ballistic cursor problem on Thinkpad i1400

Hi there. I have just installed Win2k on a friends Thinkpad i1400, but on re booting, the cursor keeps moving across the screen, and ends up against the left or right side of the screen. When you attempt to move it, it speeds back to where it was or zips across the screen to the other side! He has a USB mouse, and the track point software re installed. It was ok on his previous win98 install. The problem is that its not consistent, sometimes (but rarely) you can start the PC and the cursor never moves, and responds to the mouse movement. I am not familiar with this model. The install went ok apart from this nagging ballistic cursor problem. Its virus and trojan free. Any help would be appreciated. Cheers Chris

 

Tried swapping the rodent?