I'm reinstalling OSX via the two DVDs that came with my new Macbook Pro. The Superdrive is making a LOT of noise as the first DVD is installing clunking noises every few seconds, sometimes singly, sometimes in groups of three or four clunks. Sounds like it is starting/stopping throughout the installation. Is this normal due to the nature of the installation discs? Or is my Superdrive having problems? Thanks for any insights.