I just installed Snow Leopard on a white MacBook. Everything was fine until I went to Update the rest of the software on the computer. I hit "Install 11 Updates", it started installing, and then it just turned off. I powered up, hit the update button again, it began downloading and then powered off again. I plugged in power and powered up and now im stuck on a blue screen with the black spinning showing up and hiding repeatedly for 5-7 seconds at a time. Any ideas??