wiping a mac hard drive.

self explanatory, i need soem help wiping my sisters mac HD. she fucked it up, and i wanna do a completely clean instalation.

So wait, you boot from the CD that came with the Mac and yet the hard drive cannot be seen at all? That's BAD news. Probably a bad hard drive.

You can open Disk Utility while you're booted from a standard OS X install CD. It's just somewhere in the menus at the top. That might not even be necessary, though, because when you go to install OS X it lets you choose your installation options, one of which is a format and reinstall.

If you can't even see the hard drive after you've thoroughly double checked all the connections, you might be fucked. See if you can pull the hard drive out and try it in a different computer, perhaps a Windows or Linux box just to get some variety.