Bad laser in the DVD drive i think. I tried to fire up ubuntu I had burned on a DVD and it complained about finding the medium. Bingo.

I tried starting up the Apple Service Diagnostic CD and not DVD, it booted all the way into Mac OS X.

I cant get my USB DVD drive to boot. Shows up the disk in the drive picker on startup, but if i click it, it just goes back and refreshes the screen. I guess they dont boot from USB?