Well, I'm with Ed. The initial (clean, after reformat, _not_ upgrade!) install I did when going from W98SE to XP on my DAW took two full days, with the installer getting BSODs, having to reinstall multiple times to get it to complete at all, and the same general litany of woes. I did finally get it working, after much thrashing: but you should never assume that because a given install was trivial for you, it will be trivial for anyone else. The problems Ed is having are not a reflection on his expertise, I assure you.
I had painstakingly gathered the latest drivers for all my hardware, updated the bios and flashed the flash to the latest revs for XP support, and done everything that you supposedly need to do to have the best chance of success: but the probability is never 100%. I suspect that it is actually much lower, probably 75-80%, given the fact that we have all built machines that differ _radically_ from Joe and Mary Sixpack's gameplaying/pornsurfing machines. And when it goes wrong, it goes _very_ wrong, and it _stays_ very wrong.
I make my living working with and designing computers (unix boxes, not pcs), and I 'm not happy with the concept that the phase of the moon controls how your upgrade/install will work. However, with the Microsoft stuff, that appears to be the state of the art. Such is life. There are so many interactions between hardware and software, and Microsoft makes so many unsupported assumptions (for your convenience, of course), that their installers are really "plug and *pray*" much more than "plug and play".
Having said that: stay with it, Ed. Once you finally get all the cartoony shit out of the way, XP is rock solid. You have to jump through a lot of hoops to get the user interface junk to go away, and there are the usual nonobvious optimizations that you _must_ do to make the system really work- but once you do them, you'll like it. I never dealt with W2K itself, but XP is radically more stable than W98SE was. Seek out the XP optimization sites: I had good luck optimizing mine for Cubase based on the instructions on the Bluelife Audio Zone, and other links have been posted here. It's worth the effort.