It sounds to me like you may have the cd/dvd drive as the boot first drive (selected in bios). Check the bios and make sure your hard drive is selected as 1st boot device. Save and exit the bios.
For an install, you should boot the machine and when the post data comes up, hit the option (f11 on some machines) for boot menu, then select the cd drive as boot first. It should come up with the now quite familiar "hit any button to boot from cd." It should do this only once now.
Then when the install program reboots, it will point to the hard drive and not the cd rom, which would restart the process again. If the machine is pointed toward the boot drive then the install routine should continue as normal
Hope this helps. gl