Recently, I tried burning a disc using my 15'' Rev. A MBP. However, as soon as I put the disc in, it would sit for a second and then spit it out. I tried multiple programs, Disco, Toast, and even the default way to burn a cd in OS X however, the same thing happens. No error messsage. Nothing. I've reseted my computer. Tried multiple discs, but all to no avail.