Bootcamp - overwrote os x

alright so i haven't messed with windows in a while so i guess that was my first problem.

but i installed xp and i didn't know how to get rid of the cd and i didn't remember how to get to the set up screen for xp! so i thought i just needed to go through another install... so i continued with that!

i guess i overwrote my mac software! cause now i put in my leopard disc and it says "No bootable device -- please input boot disk and press any key"

and so i tried to reload os x onto my mac, but at the choose a destination screen no hard drive pops up to choose from!

i appreciate all the help i can get!

When in OS X setup, look for Disk Utility in the top menu bar. You will need to format the drive to Mac OS Journaled. After this you will see the hard drive in the selection screen during setup.