I've got a 2 ~ 3 year old Pentium II PC with a strange mouse problem. It works fine for a while then all of a sudden goes out of control. You can leave the mouse still, yet the cursor jumps all over the place, clicking/right-clicking/double-clicking on its own free will! The PC takes a serial mouse, so I tried another mouse (PS2 with a "to serial" adapter), yet the PC didn't recognize it, even with a basic mouse driver. I took it into a shop that apparently changed the COM port but it still acts the exact same way. Considering it to be software related, I reformatted the PC and tried reinstalling Win98 SE. On the opening setup screen, the original serial mouse started freaking out! I tried 2 other mouses (PS2 --> serial), but the PC wouldn't recognize them... even using the basic drivers the Startup Disk loads. I've run out of ideas - HELP!

Get an adapter and try the mouse on the COM2 port.

Do a site search on the left here. But I suspect a bad connection at the mobo.