I have an iMac4,1 (20" Intel Core Duo 2.0) -- stock except an authorized Apple Repair place upgraded the HD to 1TB for me a couple years ago.
It's been acting strange for a while, log in, use it for a few minutes and then get a spinning wheel, computer becomes unresponsive.
I've backed up all user data to an external drive, and now I want to do a clean install of Snow Leopard.
I have the Snow Leopard DVD (I bought it retail when it came out).
I put the DVD in. I restart the iMac, and I've tried holding down C, then D, then Alt keys on the keyboard, but it will not boot from the DVD -- it just takes me to the login screen.
With the keys pressed, during start up the pale grey Apple logo does seem to flicker to something else, might have a question mark on it.
I also tried using Disk Utility to format the drive, but it doesn't seem to want to let me do that.
So ... QUESTION ... how do I boot from the Snow Leopard DVD to do a clean installation?