Some models of flash drives feature a tiny LED light indicator, which tells you the storage drive is being detected by the USB port on your computer. But sometimes, this light doesn't come on when you plug the drive into the port. Several causes exist for this failure--some you can work around, and others you cannot correct.
The USB Port is Dead
USB ports on your computer can occasionally go dead. This is caused either by a motherboard problem, loose USB cable connection, or failure to load the USB drivers. If you plug a flash drive (that you know works in other computers) into a USB port on your machine—and nothing happens—try plugging it into another port on the machine.
If none of the ports on the front of your computer seem to be working, try a port on the back side. Test other USB devices in these same ports. If none of the ports on the front of the computer are working, open your computer case (with the power turned off) and examine the cable that connects the front USB ports to the motherboard: it may be loose. Reboot your computer and test the ports again.
Reinstalling USB Port Drivers
If none of the ports are working go to "Start," "Control Panel," and "System," then "Device Manager," and check the hardware listings. If you see yellow caution symbols or red "x" marks next to the listings for the Universal Serial Bus (USB) devices, reinstall the drivers for the USB. You may have to reinstall the drivers for the entire motherboard "chipset" package in order to revive the USB ports.
Damaged Flash Drive Blades
If the flash drive won't work on any computer, conduct an experiment: when you wiggle or lift the drive up a little, observe if the light suddenly comes on. If this happens, it is usually a sign either that the USB connector blade on the drive has become loose where it connects to the tiny flash drive circuit board, or that the USB connector sleeve on your computer has been bent out of proper fit for a USB blade. Try another USB port and wiggle or lift the drive slightly.
If the light comes on again, the blade on the flash drive has been damaged. Since there is no repair for this problem, you may have to adapt (by continuing to lift up on the drive) if you want to keep using the drive in this defective state. If you believe the USB port on the computer has been bent out of shape, use another port. If rear ports are inconvenient, purchase a USB extension cable so you will have USB access to the front of your machine.
Saving the Data
If the flash drive light comes on in an intermittent fashion, especially when you lift up on it slightly, quickly copy the flash drive contents to your computer. Replace the flash drive and recopy the files onto the new drive. If the flash drive light won't come on at all, and you can't view the contents of the drive, the data is basically lost. While there are firms that specialize in recovering data from broken flash drives, there is no way to crack open a flash drive yourself and force it to give up the contents of the drive.