Hello Game01,
Does your USB key have any sort of built-in write protection feature?
If not, then you might see if you may be able to do a
"clean all" command on the USB to wipe it clean. Just double check and make sure that you use the command with the correct disk number for the USB so as not to wipe the wrong drive. Afterwards the USB should all be "unallocated space" that you would just format.
Hope this helps,
Shawn