I had to re-image my system yesterday. I though I backed up everything, and I guess I did a fairly good job, but now I can't find one thing...my VS 2010 Product Key. I had the DVD a while back, but lost it. I had the installation files backed up, and I thought I had the Product Key, but now I can't seem to find it anywhere. This actually happened to me once before (I lost the DVD a long time ago). Last time, I got the Product Key from the installation files, or some such thing. I forgot exactly how I recovered it, but I did recover it and saved it in a text file...which is now mysteriously gone.
Knowledge is the only thing that I can give you, and still retain, and we are both better off for it.