|Check the latest round of updates from Microsoft. One of them may have affected your USB ports. |
Try other hardware in the USB port in question to verify it is working.
Is the drive being properly identified by the BIOS in the start up screens? How about in Device Manager?
Go to Control Panel> programs and Features> show updates. Expand the screen to full so you can see the dates. Updates that correspond to the problem can probably be safely removed. At least for the time being. If you Google for the KB number of the update you can find out what it was for.