Try this if your running if Running XP, Media center and readers for various camera cards.
The is to disable all the camera card devices on the computer.
Control Panel>Performance & Maintenance>system>Hardware tab>Device Manager>
disk drives
then one by one, double click on
generic usb CF reader usb device
generic usb SD reader usb device
generic usb MS reader usb device
generic usb SM reader usb device
and under "device usage" set it to "disable device"
Hope this works. If not, reverse the procedure.
Marc
Note: Also, check your drive letter assignments. The next thing is to check is to see if it's a Malware issue.