Computer can't install OS - boot from CD disappears?

I just finished putting some new hardware (an nVidia GF GTS-V, and a LiteOn DVD and CD-RW) in my computer, and decided to reformat it as well. Installation goes well until the installer wants to reboot... it reboots, but then immediately restarts the installer from the beginning instead of continuing the installation from before. Normally I'd get a "Press any key to boot from CD..." option, but that doesn't happen here. I have tried both WinXP Pro and Windows 2000 with the same effect. Thinking I may have gotten a defective DVD drive, I hooked up my old reliable Toshiba CD-ROM... exact same deal. All of my BIOS settings look accruate, and I've actually reset all of them to default. Any ideas?