Good evening/night, I tried looking for solution on Google but did not find it so I decided to register here and see if anyone could help me. I am running Leopard on an aluminum iMac from late 2007 and everything was fine. Yesterday I bought Snow Leopard, put inside the DVD and clicked Restart. The computer restarted and the Apple logo appeared. The spinning wheel was spinning for like 7 minutes and then the computer just shut down!! I tried again and again but the problem continued. So then I tried different approach.. I took out the DVD and restarted the computer. After the startup sound I held ALT until the Macintosh HD appeared, inserted the CD, it was recognized so I selected it but the same damn problem. Apple logo and then shut down. Today I was able to exchange the DVD for another one (thought that maybe a bad install disk) but.. the same problem with the new dvd!! So now I am worried that I have problem with my iMac. I hope that it is not broken because I do not have money to fix it. Does anyone have any ideas of the cause and solution to this?