plug it in to the usb drive, go into device manager, in there you will see universal serial bus controller, hit the plus sign you will see something that says USB mass storage device, right click on that and select uninstall. you will see it disappear from the list, unplug the USB drive and then plug it back in and you should hear the beeps and it should work again.
if that doesnt work there are virus that change a registry entry to disable it ill tell you what to look for if above doesnt work.