What likwid said. When you boot with the CD inside it will read "Press any key to boot from CD..." and do just that. If that doesn't work boot into the system BIOS, go to "boot Sequence" and place your CD-Rom before your hard drive and try again.
I guess I was just assuming if I threw in my xp disc and tried to re-install xp it would prompt me that I did not have admin rights to proceed...but I have yet to try it so I guess I will now