If you repeatedly (and rapidly) insert and remove a USB device, the USB port may stop responding, causing it to not recognize any USB device.
To resolve the problem:
1. Right-click My Computer and Press Manage.
2. Double-click Device Manager.
3. On the Action menu, press Scan for hardware changes.
4. If this does NOT fix the problem, Restart your computer.
NOTE: Wait several seconds between unplugging a USB device and plugging it back in.
NOTE: It is not yet known whether this behavior is a hardware or software issue.