i have an ibm thinkpad t21. there's a piece in the dvd drive that sits on the spinning part of the dvd drive and its used to make sure the dvd doesn't move. this piece fell off and i was wondering if anyone knew how to put it back on. the piece is circular and a little smaller than a dime. it almost looks like a metal clothes button. i need this put on, so the dvd won't move once i put it in.