How do I recover files from an USB flash drive?
Solution 1:
PhotoRec is file data recovery software designed to recover lost files including video, documents and archives from hard disk drives, CD-ROMs, and lost pictures (thus, its 'Photo Recovery' name) from digital camera memory. PhotoRec ignores the filesystem and goes after the underlying data, so it will still work even if your media's filesystem has been severely damaged or re-formatted.
PhotoRec is free, open source and portable (doesn't require installation).
If you're looking for professional data recovery software, then your best bet is WinHex (or the 'light' version Davory).
WinHex and Davory are shareware - try before you buy.
Solution 2:
First thing I would try is to plug it into another computer - I have no idea why, but ever since floppy drives, this works more often than not.
If it still does not work, you will want to try generic recovery tools.
I recommend Recuva for free, or if you want to pay then R-Studio
Solution 3:
Assuming it's also not showing in the BIOS when plugged into a system, and since it's not being recognized by the OS(s) you tried, the bad news is it sounds dead. The better news is, it may just be the power sub-system, and the data may still be in the flash memory.
I'd have to say your best bet is to send it off to a professional data recovery place that does flash media. Many (most) offer free evalutation and quotation, you just have to pay the shipping. Most also offer that if in the end they can't get it back, you don't pay.
You can then decide if the recovery fee is worth it, without investing much.