Restoring 8.6 On My Imac, Why do you need to hold down C? Options

[gorillacake]

O.K. my imac is a mess and I want to completely erase my harddrive and reinstall 8.6 from scratch.
I know I need to use my software restore disc but everytime I try to start the computer (disk is inserted) and hold down the c key I get a black screen. What's the difference between just clicking on the restore cd Icon on my desktop and actually restarting it and holding the c key?

[formatj]

Have you tried starting up from the 8.6 system disk by going to Apple Menu>Control panels>Startup Disk and choosing the 8.6 disk?

[Bart S.]

I might be wrong but I think the Restore CDs came along with a main Installation CD (?...). This Installation CD should be the one used to boot using the C command. The Restore CDs should be used (as their name implies it) to Restore particular elements/applications.

[gorillacake]

Well what happened was I installed 10.2 without updating the firmware resulting in a completely messed up mac. The screen either has this red tint to it or even worse fades to black. Anyways, the computer has 8.6, 9.2 and 10.2 all on the same harddrive. My mom started the thing in 8.6 and now I can't get back to 9.2 or 10.2. For some reason the computer won't recognize the other OS's when I go to my startup disk. So I'm thinking my best bet is to do a fresh resinstall of 8.6 (I don't care if I lose everything) then 9.2 (where I can update the firmware) and then 10.2. Hopefully this works. So I'm not a total dumbass as my first post probably implied ( although I did upgrade to 10.2 without the firmware update doh!). Does this sound right to Ya'll.

[gorillacake]

O.k. for the benefit of any newbie who has followed this post I will follow through and talk about my sollution. I realized that since I had the 9.2 install disks there was no reason to install 8.6 first. So I inserted 9.2 and restarted the computer holding c so as to start up from the disk. I could then initialize (erase everything) the hard drive and do a fresh install of 9.2. I then went to apple.com (after setting up my internet connection), downloaded the 4.8.1(I think) firmware installer and followed the detailed directions on how to do this. Make sure you read these because you have to hold in the programmer button on the side of your imac while starting it up to install the firmware. Your computer will then start up in 9.2 all shiny and happy. There was a big difference in the graphics resolution even from when 10.2 wasn't installed. I then did the easy install of 10.2 and my mac was happy! I guess the important thing I learned was that in order to initialize a hard drive you have to start up from an OS install disk. Hope this helps someone.