Hi all, I've got a late 2007 MacBook running 10.5.8 and I want to upgrade to Snow Leopard...but the disk will constantly spit out! It will spin for a little while (at about 6x), stop, then eject itself. Sometimes I do get to a point where the MacBook will recognise the disk and it will begin the installation...before clonking out and saying there's a message with the disk. There is absolutely nothing wrong with the disk... I urgently need to upgrade back to Snow Leopard though! Anyway that I could fix this? Thanks!