1. Plug in the USB Drive, go to my computer, right click on this drive icon, select “sharing and security” or “properties”, select “tools” tab, click on “error checking” and see what happens, it should work.
2. The files might have got corrupt on this media may be due to it is very old, has been used very extensively, has been formatted many times, bad sectors, phyical damage to the media.
3. If it is physical damage a hardware vendor can fix it (less possibility), retrieve your data on another media (high possibility)
4. Physical damage could have happened if it has been exposed to heat, or kept near some other device having strong electro-magnetic field.
Above all if nothing happens, you can sacrifice the device, but for data, you can go for point number 3.