Dead USB flash drive
You could pull it apart and check for a physical problem with the drive. If there isn't an obvious physical problem then either:
- One of the chips is fried internally. Could be from static electricity or heat.
- Try this set of instructions and see if that helps at all.
- Download and install the HP Drive Key Boot Utility
- Open the desktop icon and select the correct flash drive under device
- Select the file system you want to format to (FAT, FAT32, NTFS)
- Tick Quick Format
- Click start
In you need the data recovered, you can try several solutions which cost various amounts of money. I have not researched any of them and cannot give an objective opinion. Next time make backups and don't trust a USB drive.
Does it appear in Device Manager? Click Start, Run and type devmgmt.msc.
If it does, there are a couple of tools I would recommend. Firstly, PhotoRec which is free.
PhotoRec ignores the file system and goes after the underlying data, so it will still work even if your media's file system has been severely damaged or reformatted.
Alternatively, I purchased and had great success with a tool called R-Studio. It comes at a premium, but hey you get what you pay for.
Additional file recovery algorithm. R-Studio not only analyzes file systems metadata ( all file types are supported ) but additionally searches for files of known types ( see list of known file types ) using typical features of their structures that allows the user: - to increase the quality of file recovery when the file system is not damaged; - to recover files that are not recognized in file system metadata and not found during a disk scanning procedure; - to recover files from devices with unknown file systems, including HD, CD, DVD, floppy disk, Compact-Flash Card, USB drive, ZIP drive, Memory Sticks and other removable media.