HP desktop won't boot

hey guys,

the IT department for the company I work for gave me a gutted out HP desktop.

It's missing the hard drive and RAM, but everything else is intact.

I placed couple sticks of ram and a old hard drive I had kicking around.
I popped in my XP disc, in an attempt to reformat it.
But the computer does not give me the option to do so.

I tried configuring the bios (i.e. disabling Ethernet boot, setting CD-rom first for boot up priority, etc.) but I haven't had much luck.
Any suggestions?

I thought it'd be pretty straight forward...

thanks in advance