After looking into this a bit I saw that this solution was able to help many others with your same problem.
Shut down your computer completely, unplug the power cord from the back for at least a minute (this drains the power from everything). Then power back up. For many people all of their USB ports were flaking out, first one, then another, then the whole USB hub was gone. This little trick should have them all back up and running perfectly.
It may be damaged. Inside a flash drive are a few metal contacts that connect to the chip inside. Cheaply soldered contacts will break off that chip, and stop working.
You can sometimes get them to be recognized briefly by moving the flash drive around in the usb port. The best way to recover the data would be to take it apart, and hold down those contacts. The computer will pick up the drive, and you can transfer the data off of it.