Here is a fun project if you are up for it. We seem to have a thief in our midst. The latest items to disappear are flash drives if we don't lock them up at night. Do you know how I could put something on the flash-drive so that when they used it, it would email me something identifyable?

I think your are clutching at straws. for it to work it would have to plugged into a computer with an Email clients installed or and Email application like Sendmail and connected to the Internet or alternatively put you own Email application on the flash drive. Its not that difficult, Trojan writers do it all the time. You could end up writing code that consumed a large proportion of space on the flash drive and even then, a decent Anti virus will probably block it thinking it is a Trojan trying to send Spam. You are going to have to keep locking them up at night. Stuart

It's true what Stuart said about relying on the presence of an email client on the thief's computer, but you can easily get around that. Instead of sending email, just do an HTTP request for a dummy URL. You can copy the open-source wget.exe program on the flash drive, and use it to request something like http://myserver.example.com/%USERNA... Then all you need to do is look at your web server's logs, and it will show you someone accessing it, and his username will be coded as though he had requested a web page by the same name. The server log will even show you the IP address of the thief's computer or router. You can put all that in an autorun file.

Warning: Auto running programs are easy to prevent, and not all versions of Windows will default to running Autorun from a USB.

Thank you very much for the responses. I'll keep you posted on what happens.

Or you could just keep a lookout for anyone selling "cheap refurbished USB drives" on ebay...