I think I just want to reload the operating system again. So is it as simple as putting in the disk and letting it do its thing, like the procedure for a PC?
Do you have files that you want to save first?
If so, we can try to rid you of any malware first.
But, yes, put the CD in, restart the computer, once you hear the Apple sound, hold down the C key to boot from CD.
Though, I have never run the OSX installer. I am thinking of OS9 and 8, which I have had to reinstall multiple times.