Warning: The tools in
2. and
3. (below) will format (ie remove all data from) your flash drive, but as a last resort it is worth it.
1.
Check for a tiny switch on the flash drive, some have this
Confirm it is not in the Write protect position
2.
HP USB Disk Storage Format Utility
This will format most USB flash drives
It can be known to recover Flash drives that are un-responsive too.
3.
If that doesn't work try this one:
Hard Disk Low Level Format Tool (USB Flash drive "format" that is

)
4.
The following entails editing the Registry
warning: If you are not comfortable in doing this, or inexperienced with the registry, then don't do it ! Incorrectly modifying the registry can have drastic effects on your system.
Start->Run-> Regedit
Expand: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorageDevicePolicies
(Note: if this key doesn't exist, then disregard this option, and close Regedit)
Double click on the string ‘WriteProtect’ and change the ‘Value Data’ box to ‘0’
Close Regedit, and Restart
Please reply if any of these options helped you
