I had a thumb drive that acted like it failed on me. I had data on it and it was working fine on both winXP and Win98 computers to transfer files back and forth. One day when I plugged it into the WinXP computer, the drive showed nothing on it. It was like everything on the drive was gone. I did not want to loose the data that was on it so I did not try anything in WinXP. I later plugged the thumb drive into Win98 and everything showed up fine. In Win98, I transfered all the files to the hard drive and then copied the files back to the thumb drive. After that the drive showed the files back at the WinXP computer. I also forgot to say that when the files did not show on the WinXP computer, I had also try the thumb drive in two other XP computer and the files would not show up on any of the WinXP computers.
I do not know what was wrong but the drive has worked since then. You may want to try your drive in another operating system. In Win98, you will need to install the drivers for your thumb drive before the operating system will see the drive.