iMac takes over 15 minutes to turn on.

Ok so since yesterday every time I turn on the iMac it goes to the blank white screen and takes atleast 15 minutes if not over that to go to the login screen. Once I get there everything else on my computer is fine and works the way it has since before this. I play World of Warcraft on it and the parents think I am burning out our graphics card or something since we had to have it replaced a while back. Is this true, or is the problem being caused by something else entirely?

Let's start with some simple things:

- what model iMac do you have, and what are the specifications?
- what size hard drive do you have & how much free space does it have?
- when was the last time you repaired permissions?

- Nick