Bizarre Vista Install Problems

I will attempt to be as concise as possible, despite the evolving nature of this problem and my numerous varied efforts at solving it.

Starting from the beginning:

I have a Dell XPS Desktop purchased in the summer of 2005. Its stats:

-Windows XP Media Center Edition, SP2
-Pentium 4, 3.4GHz
-1 GB RAM
-250GB SATA Western Digital HD

So I want to install Vista because I can get it for free from my school. But I don't want to get rid of XP, since I've heard shaky things about Vista, and XP runs fine (except for the 15-minute startup time). To pursue this end, I purchased a new hard drive (Western Digital SATA 250GB; basically the same type as the original HD, with a faster transfer rate). The idea is that I'll set up a dual boot system with Vista on the new HD, while maintaining the old XP installation on the old HD.

The problem first appeared when I attempted to install Vista on the new hard drive. Booting from the Vista DVD and starting the installation from within XP produced the same result: the installation would finish "copying files" and move on to "expanding files". Once in the "expanding files" process, it would proceed to 37% completion and freeze. After 20-30 minutes frozen there, an error message would appear with the code 0x80070003, claiming that the required file could not be located. The only thing to do at that point was to restart. After restarting, a BIOS error message would appear, claiming that the new HD was no longer detected. It would continue not to be detected until such time as the computer's power was physically turned off. However, after turning the computer off and back on, the drive would appear again as if nothing had happened.

I decided that the problem had to be with the new HD, so I arranged for a replacement drive on Western Digital's website. The new one came and produced the exact same problem. I talked on the phone with Western Digital for some time, and they suggested the new SATA cable I had bought for the new drive might be defective. So I bought a new cable, then another, then I decided to use the SATA cable that used to be attached to the old HD, knowing that it has worked perfectly for almost two years. (Incidentally, the new cables work perfectly with the old HD). The new cable did at first seem to have a positive effect: the Vista installation completed! Hurray! I started using Vista, and it worked just perfectly.....for about 2 hours. After that much time (varying from 30 minutes to fully 8 hours at one point), the following happens: everything freezes (except cursor movement, which still works) for 15 seconds-2 minutes, then a blue screen appears (for about 5 seconds, with no text or error messages), then the computer restarts and the BIOS recognition problem returns.

So, I got the second new HD replaced by Western Digital. They sent me a new drive of a slightly better model (320 GB instead of 250), since they were totally baffled by the problem. It so far has returned to the original problem: the Vista installation will not complete, freezing at 37% "expanding files".

Other things I have tried:

-plugging the new HD into all of the four SATA ports on the motherboard (including the known good one that the old HD was plugged into)

-using the new SATA-style power (2 different power cables) and an old legacy four-prong power cable

-rearranging the physical location of the drive within the desktop case (fearing that overheating was the problem)

-installing the driver for my Intel SATA controller during the Vista installation process

The only thing that I can think of that has remained constant is the Vista DVD itself. I will reburn one (since I get Vista through my school, they provide an ISO and we burn our own installation DVDs), but I will wager a large amount that that will not help this problem. Can anyone suggest any other solutions?