k, boot that cd, and when oyu get to the darwin boot menu, press f8 on your keyboard so oyu can type in more options
type in "-s" (without quotes) and press enter
it should start loading, and you can see the text on the screen
after a while, it will ocme to a shell like thing, where you can type stuff
assuming that you installed osx to your first harddrive, type in (qwithout quotes)
"fdisk -e /dev/rdisk0"
it should comeup with a list of partitions, and their filesystem next to it
look at the number for the one that says hfs+ (or something like that), then type f (insertnumberhere)
after that, write "w" without the quotes
then "q" without quotes
try rebooting now