The mobo is a ASRock K7S8X with a Athlon 2400 thoroughbred and I have one card of 256mb DDR 333. The mouse is a standard (not optical) 2 button PS/2. Properies are all correct and "assume wheel is present" is ticked. No conflicts.
Done a very recent AV scan and Spy Bot. No problems.
RAM is also working fine.
I am sure the clue is in the fact when I power up P2 it works perfectly. Turn P2 off and the mouse dies off within 2 minutes (note it is not instant) I have movement in the horizontal plane but the vertical plane gradually fades away to zero movement. Using a process of elimination I am begining to think that the mouse socket has a problem.
1) KVM switch has no problems
2) Mouse has no problems
3) RAM has no problems
3) No virus or spyware
4) No cabling problems
5) I only have this problem on P1
6) Problem persists even when mouse is plugged directly into P1
without the KVM switch
I am going to borrow / buy a USB mouse and see what happens.
Will report back to you
Thanks for your interest and help
FBW