I've been through many threads and youtube videos about this upgrade and everyone seems to be able to do it just fine. I have a black macbook (2006). 10.4.11 OS X. 2GHz Intel Core Duo. I tried everything it seems. I backed up everything onto another hard drive, booted to the installation CD (Snow Leopard upgrade $29) at the start-up (pressing option) at startup with the CD inside. After clicking the language of choice, I get an error saying that it requires 10.5 or above to upgrade. The only options from this point is to restart the computer or restore from backup. I looked everywhere to see if people had a similar problem. Every video I saw did not have this prompt. They were able to get to the following picture instead to install. I have tried erasing my entire hard drive...and it still recognizes that it is 10.4. I've tried erasing the hard drive, disconnecting the backup drive, so the only thing it can start is the cd and it still knows it is 10.4. HELP!