sharkbuster,
Without any details on your hardware or OS, and am going to take a complete stab in the dark. Try using a different USB Port. If you are using the USB Ports on the front of the computer or the Ports that are in the PCI Slots, then open the computer, unplug those ports from the motherboard and plug them back in. See if that helps.
Take Care,
Richard
P.S. flyingwysiwyg looks like our posts crossed.