Stefan - 11:36 pm on Sep 1, 2008 (gmt 0)

When this has happened to me, the drive was bad.

Same here, three times now. As kaled said, CD drives are the weakest part of a computer - they should sell them by the half-dozen so you can just slap a new one in every few months. It's really not very hard to do - just read up a little first, and don't shuffle your slippers across a thick carpet before you touch things ;-)