After making all of these changes, I checked the system BIOS and, sure enough, DEP was now an option. So I turned it on. Then I recovered the original Windows XP partition. After a reboot, I updated the chipset drivers and then installed new graphics drivers.
At this point, Windows XP began generating memory errors. These weren't due to a hardware incompatibility, but to a bug in which a Microsoft service would crash repeatedly. That told me that I was running Windows XP Service Pack 2, which had some problems when Data Execution Prevention was turned on.
It's never simple, is it? I updated to XP Service Pack 3. The errors continued, but less frequently.
Windows 8 redux
Keeping my fingers crossed, I popped in the Windows 8 DVD and walked through the setup process. This time, it all went smoothly. The system rebooted a couple of times, and soon I was running a very hot, very noisy Windows 8 system. A quick run of the Windows Experience Index generated a whopping 4.4 score, with a processor score of 5.5. Modern CPUs tend to max out at around 7.0 to 7.8. Still, that 5.5 rating was better than I had expected.
To be fair, the hardware build that I started with wasn't the hardware build that I ultimately used for Windows 8. The graphics card swap introduced a particularly significant change. Even though the Radeon HD 6450 is an entry-level, low-end graphics card, it's DirectX 11.1 capable, which instantly made my system more responsive in Windows 8.
Still, even discounting the GPU, the system seemed more responsive when running Windows 8. The 2GB of memory and the slow hard drives certainly made things drag, and the old CPU didn't help, but the whole affair hung together much better than I thought it would.
Bottom line: not a great idea
Few Windows XP users are likely to make the jump to Windows 8 by upgrading an existing XP system. Still, I learned some things from this crazy little project:
An in-place upgrade of Windows 8 over Windows XP isn't really an upgrade. It's really a clean install that saves all of your user files, but kills your applications.
Despite blowing away your software, you can't do an in-place upgrade with 64-bit Windows 8, even if the CPU is 64-bit capable.
For Windows 8 to work, the system must support data execution protection, and DEP must be enabled.
Windows 8 can actually run on 2GB of RAM!