Have you tested the pen drive on another PC with different operating system? If not, please try it and come back tо the topic to tell me what happened. Please, make a printscreen of what you see оn the Disk management menu when you insert the USB drive.
I also would like to know if you have tested the USB with any software for drive repair. Its manufacturer probably has designed a tool for testing the USB's health status.
You could always check your pen drive with the Windows tool in Command prompt.
The Command prompt has to be opened in administrator mode and there you have to enter the following command:
chdsk X: /r
replacing the letter X with the one that has been given by oyur PC to the USB flash.
Western Digital representative