ps2 mouse failure

hi,

strange tale to tell about ps2 mice, a few days ago the ps2 (bog standard wheel type) mouse on my win98 machine started to play up, erratic behaviour etc, then died completely. tried another (spare) mouse in the ps2 port got a 'windows failed to detect a mouse message on bootup. looked at the irq's and irq 12's been taken by something else, so i reserved it in the bios, message gone, windows says it's found a mouse and installs driver, but still no movement tried both ps2 mice again- no joy. plugged in an ancient serial mouse, worked fine, as does a usb mouse, but still don't know why my ps2 port has died.

ok now the wierd part. today on my XP machine, playing a game, suddenly mouse freezes (it's a ps2 mouse), game crashes. reboot. mouse movement is erratic, think to myself oh oh seen this before, then mouse stops working completely. reboot - same thing mouse works for a while then goes erratic then dies. no mouse control. no error message on reboot but no mouse movement at all. plug in the usb mouse, all is well.
so the cure is simple - tomorrow i go and by two usb mice.
but the question is why should two ps2 mice, or ports, drop dead within days of each other, on two different machines, different OS, different mobo's. and before you ask no i never plugged the dodgy mouse from a few days ago into the xp machine so it can't have killed both ports. infact i don't know if the port on the xp machine is dead as i haven't tried my third ps2 mouse in that one. haven't tried the suspect mice in another machine yet, but on the win98 machine a previously working spare failed to work, so i suspect the port or drivers. the only reason to suspect the mice is they are the same make and probably similar vintage.

anyone seen anything like this before?