Make sure that
the flash drive is good before you do anything to your computer.
Can you read/write to it when it is plugged into the back panel?
If yes, case wiring is messed up.
If no,
Try the drive in another computer. Can you read/write to it there?
If yes, your computer hardware or software is messed up.
If no, you know the drive is bad because it does not work in two computers.