I tried to DL dmg2iso from the link you gave me and that doesn't work, i might have to go fishing for that i suppose, the exe. file flashes something really fast in the MS-dos black screen mode then goes away, it doesn't do any thing. Now, you told me to hold down C but i don't have any OS installed on the MAc (blank Hard drive) so it would never even show on the macs desktop. do i still hold down C??
If your hard drive is blank, you could format it with the Mac OS Restore CD/DVD that should have came with your Mac. Otherwise, yes, hold down the C key while starting up your Mac, and your Mac will boot up from the Mac OS install DVD - the installer will then format your hard drive.
once your booted to the cd/dvd you need to open disk utilities and format the drive. It will seem like there is no drive installed unless you do that first, since its a new drive with no partitions.