Having trouble with a USB thumb drive.

This device worked in the past, on this laptop.
The trouble is, while Windows recognizes it, it is not assigned a drive letter under "My Computer".

The device is recognized correctly by Windows, and it DOES appear under USB decvices in device manager.
It is also correctly managed by the "safely remove hardware" icon. In fact, the Remove hardware app tells me that it is assigned to Drive "F". but it's not.

I've tried all USB ports. The laptop WILL work with an external Hard drive. That is assigned a letter, I can r/w to it, happy day.

This drive worked on my home computer yesterday, and this morning when I plug it into work laptop, it fails.

I've tried to refresh, and scan for hardware changes, no dice.

Stupid computers! Help.