Endless Black Screen Instead Of Rebooting During Installation?

Have Windows 7 on my laptop and it's been working OK so far. When my WinXP install on my desktop started acting wonky and refused to launch except in safe mode, I figured I'd go ahead and trade up to Windows 7 since I'm a student and can get a copy for $20.I pulled all the data I wanted onto a USB drive, then started installing. Did a clean custom install; deleted both previous partitions and made a single new partition for it to install on (plus the mandatory 100MB partition). It chugged along and seemed to be progressing nicely: Copying files... check. Expanding files... check. Installing features... check. Installing updates... check. Completing installation... VIDEO MODE NOT SUPPORTED. Suddenly my monitor doesn't understand the output it's getting. The system doesn't see the keyboard either: caps lock & num lock buttons don't toggle their associated lights. So I gave it an hour. Still nothing. I figured it must have locked up, so I power-cycled it, hoping it had completed the installation. No such luck, I get an error message saying the installation ended unexpectedly and I have to restart. So I restart. Same thing happens.

During the portion of the install just before the final reboot, while it says, "Completing installation..." the screen goes black to show a single blinking cursor in the top left for a second or so (like it kicked out of the OS), then goes black & says video mode not supported, like its receiving invalid input from the computer. I connected another monitor and instead of saying video mode not supported, it just shows a black screen, like its getting good output from the computer but the computer just wants to show all black (this monitor does have a 'video mode not supported' equivalent screen, which it's not using in this case; that's why I think it's getting good output from the PC). I know the system isn't reaching the actual reboot, because it doesn't do the 10-second countdown before automatically rebooting, it just jumps straight to the black screen.

Machine Stats Processor is a 3.0GHz Core 2 Duo. Has 2GB of RAM. GPU is an Nvidia 8800 GT. Monitor is a Dell 2007WFPb. Disc I'm installing from says "Windows 7 Ultimate 32-bit x86 Upgrade: Pre-existing OS License Required (Product Key Required) - September 2009 Systems Student Media".

Current Things to Try Install WinXP and give Upgrade Advisor a shot. Current Operating System, pre-install- Never multi-booted before, not planning to start now. Current Hardware- 1 SATA hard drive- 1 SATA DVD drive- 1 USB external drive, but not connected during install- Didn't see any disks with an exclamation point or yellow triangle - Not a new HD; as I said, it's one I was using before, I deleted the two partitions I was using with WinXP, made a single new partition (plus the mandatory 100MB one), and formatted the new one using the installer's Disk Manager Windows 7 installation details - Disc says Windows 7 Ultimate 32-bit x86 Upgrade: Pre-existing OS License Required (Product Key Required) - September 2009 Systems Student Media ... I saw on various forums before I started that Upgrade versions could do clean new installs as well - 32 bit (x86) version - Bought a legit DVDInstallation Media- From a DVDThe procedure and speed of burning the ISO to DVD has been the most frequent cause of installation failure- Bought itOther- No overclocking?