Just to give you an update, I've had another instance to prove the rule that nothing ever runs smoothly for me pc-wise.
I figured, before asking, that the Raid would work but that Windows would require a reinstall, which seems to be where vanp1992 and meanman were heading as well. So I rigged the hardware up, and configured the bios to activate Raid on the required slots. Hey presto, it was detected and shown as healthy. So far so good. Then I go through the Windows setup, and sure enough it detects my previous installation on the Raid, which I choose to repair. All's well until the very end of the installation when it clears temp files used and restarts. This time, the pc freezes with a black screen and a white cursor. After about 10 mins of waiting to see if it'll kick itself out of it, I manually restart, at which point normal service resumes, the resolution callibration goes through and I reach the desktop with all programs/settings intact. Very strange. After some time I go to restart the pc via the start menu, and Windows shuts down. But just before the pc resets, it freezes with no monitor input. When I push the reset button, it works fine, until I want to restart again. Same deal.
So I decide to repair install again. This time it freezes half way through, during the device installs. Various hardware configs later, I give up on trying to repair, but at that point I had too much info on the raid I still hadn't backed up. So I install a fresh XP onto a spare IDE drive, along with all mobo drivers, and lo and behold my raid is perfectly good, with all files and folders intact, along with what looks like half an XP installation... With the IDE XP shell and a few programs like Nero, I go ahead and back up about 100GB of data onto 4.7GB DVD's, and then try a fresh installation onto the raid, which I reinitialize just for good measure. This time, it worked flawlessly.
At least now I have disk backups of important data (whereas before I was reliant on physical hard drives), and a working XP on the Raid0. Now I'm faced with the prospect of reinstalling around 100 programs which I use frequently as well as the 20ish games I can now play with what I can say is a very nice card.
). The thing is, I've got a Raid0 running at the moment, and I've just got XP exactly how I like it, so I'd quite like to preserve it.