i am currently running tiger on my 2.16 ghz intel core 2 duo macbook, and have bought the leopard upgrade. when i insert the dvd into the optical drive, it sounds like it's trying to read the disc, but then spits it out. nothing happens other than that. thinking it was something to do with the dvd itself, i went to an apple store where i bought it and replaced it with a new one. the same thing is happening with the new disc, but my computer's optical drive reads cds, movie dvds, and my tiger setup dvd just fine. i've tried resetting my pram and holding down c while restarting, but nothing seems to work. i know others have experienced this problem and would like it if i knew what they did to fix it. thanks