When you unplug and plug in the printer again, does Windows make any sounds or are there any notifications that pop up in the lower right corner?
If not, it's probably one of three things:
1. The USB port no longer works. Test the printer in another port or test another device in the same port. If the printer works in another port, or if another device fails to work properly in the printer's old port, then it's probably an issues with either the USB port or motherboard drivers.
2. The cable is shot. Try a different one. If you don't have one, they're fairly inexpensive and can be bought at most any computer shop or electronics store, and I think even Wal-mart has them.
3. The printer is shot. Verify this by trying it with a different computer and even another cable on a different computer, just to be sure. If the printer doesn't work on another computer even after changing cables, it's most likely an issue with the printer (perhaps the port on the printer is loose, or something broke internally).