USB Flash does'nt work

Do you have a USB flash drive that just won't work anymore? Assuming the hardware is undamaged, you could try formatting the USB drive.

1) Insert the flash drive into a USB port on your computer. If it is detected, it should show up in your "My Computer" after a couple of seconds.
1.Try right clicking on the USB drive icon and then left click on format. Select NTFS for windows operating systems beyond 98. Click "start" and formatting should begin. Note: Formatting will erase everything on the device.
2.Try using the USB drive again as before.

Alternate method.

Backup all data from your hard drive to another hard drive or CDs or DVDs.
1.Turn off your computer.
2.Insert the USB drive to a USB port.
3.Turn on your computer.
4.Hit the F8 key when prompted to get to your system bios. Some computers required the Delete key or F2 instead of F8. There should be a note on the screen that specifies the key.
5.Navigate your bios (usually using your cursor keys) to boot from CD drive first. Save and exit.
6.Insert your operating system disc aka Operating System Restore disc. Your computer should restart. If not, restart it yourself.
7.Follow the instructions for installing your operating system. When the option to select which drives to format comes, you should be able to see your USB disk in the list.
8.Format the disk with FAT32 for Win98 or previous. Format with NTFS for anything after e.g. NT, 2000, XP etc.
9.Depending on your options, you may be able to opt out of the operating system install at this point. If it was running well beforehand and you can, leave your other drives alone and quit the re-installation.
10.Reset the computer to boot from the disc drive the operating system is on instead of the CD drive as before. You should have your working flash drive detecting and usable now in windows.
11.If you didn't get the option to opt out of the re-installation, continue to follow the instructions onscreen and complete the re-installation, formatting whatever drives are required. Note: Do not try to install your operating system onto your USB disk drive.

Search around for a formatting tool to reformat your drive beforehand. Re-installing an operating system is not a task to be taken lightly.
Things You'll Need
Your operating system (restore) disk.
Your operating system activation code.
Your operating system serial key.

Please post back if you have any more problems or questions.

Go into "Control Panel"
Open "System"
Click the "Hardware" tab
Click "Device Manager"
Under "Disk drives" find the drive that is causing the problem.
Right click on the disk drive and click on "Uninstall"
Expand Universal Serial Bus controllers section.
Right-click every device under the Universal Serial Bus controllers and then click Uninstall to remove them one at a time.
Exit "Device Manager" and Restart the PC.

Free Hard Disk Utilities: Recover Deleted Files and Lost Data

http://www.pcworld.com/downloads/collection/collid,1295-order,1-c,downloads/files.html

Go to the manufacturers site and see if they have any help.