|If you unplugged it without using the 'safely remove hardware' option then a critical file allocation table (or what ever it is called these days) may have been corrupted by not closing it properly. Try it on another machine. Try plugging it in the same machine it was in when originally unplugged but while that machine is off and then starting it (probably not useful but worth a try). Use 3rd party recovery software to recover data on the drive (many here recommend Recurva I think it is called, but I have no personal experience with it) and format it.|
You have to be a little bit crazy to keep you from going insane.