When I head home for the evening I shut down my computer. When I do this I have to unplug any USB drives that I might have been using. Frequently I request to remove the device from Windows and it pops up a little message saying that I can't remove the device just now because something is using it.
This is frustrating because I'm the computer user and I'm not using the drive. I found this little utility the other day which works a charm. Just right click on the drive to be removed and choose unlocker. It will tell you what processes have locked the drive and offer to unlock them or kill them.
I got the reference from Maximum PC magazine.