How to wipe hard drive that has no OS

Hello,

We got a fresh built computer Friday w/the following components:

ASUS m5a97 motherboard
Seagate Barracuda 750GB Hard Drive
Radeon 4350 graphics/video card
450v power supply

BIOS is accessible, EZ or Advanced mode

We have and external ASUS CD drive.

Problem:

We tried to load a DELL Windows XP Home OS CD on there.... OOPS. Didn't work because it could not detect hard drive when we selected INSTALL XP. It went fine until that point.

We have a disk now that is supposed to work. It won't.


QUESTION:

Did the DELL disc mess up the hard drive so that we can't load our new disc?

How can we wipe the hard drive (BIOS is only thing available) so we can try the new disc again??

Please help!