Win XP freezes after USB Stick is plugged

hi there,

if i plug a usb mass storage stick (i tried different different sticks) to my computer (win xp pro sp2 @ dell gx270) the desktop freezes completly. only thing i can do is open the taskmanager and log off. when doing so it gives a warning “cannot stop cardreaderlookup”. after logging in again, everything works fine.

any ideas?

gtx
stephan