I have a homebuilt, Asrock MB, ATI graphics, legal and updated XP Pro OS. Epson printer via usb, system has RUN very efficiently for a couple of years until very recently I have had the following occur - if I insert a 2gb usb memory stick into any of the six usb ports (2 front, 4 rear) the microsoft optical mouse shuts down; if I insert a 32/64mb usb mem card the mouse continues to work! I have tried different  2gb sticks for the same result, XP tells me all hardware/drivers are working and are the BEST available. Any HELP as to where I should go next please.

Thanks

KiwijimDo these sticks have the U3 software installed ? ?

Have you tried re-installing the mouse software ? ?Unable to TELL if sticks are U3 software- how do you do that? Nonetheless, following your advice I downloaded and installed Mr Gates' latest intellimouse offering and got no difference. However when on the microsoft website I saw an article about usb part of which said to go into device manager and 'identify hardware changes'. This I did and lo! the 2 mb sticks work - but only one at a time - probably a power issue now. I have no need to USE multiples so I'll settle for that! 

Thanks patio!Good News...wasn't my fix but glad it worked out for you...
Stop by anytime !