I've reset the PMU/CMU and PRAM, still have apple logo and spinning wheel. I got a restore disk, but it was the wrong rev....

My iMac wont boot up past the white apple screen with the spinning circle. This happened after my mac froze then i had to...

I've done this, still have apple logo and spinning wheel. I got a restore disk, but it was the wrong rev. I think the machine told what the correct was. But I can't get back to that point. How do you the OS from the CD drive?