I was trying to install Snow Leopard on my MBA via a remote DVD drive on my PC. The installation took about an hour and I got to the screen that says "Install Successful". It said that the computer needed to be rebooted and I clicked the button at the bottom of the screen that said "Restart". When I did that, I got the colored pinwheel and it's been sitting like that for the last 20 minutes. This is my first Mac and I don't know much about them so it figures it would happen to me. What should I do?