I'd never recommend someone buying something that their computer won't support, but sometimes you can get lucky. My CotN froze, locked up, chopped, you name it, on my 2.8 P/4 with 512mb and a 256 Radeon, after a clean install of XP. My wife's runs like a champ, and she has a 700 mhz with 128 of RAM and a 32mb Radeon running on 2000K. Not to mention 50 background running programs, spy programs, and a few dozen viruses she tends to pick up. I don't even see how it loads. The game scrolls a little slow, but it works fine and has not crashed yet (been playing two weeks for a few hours a day).
I might want to add a little help info in here after contacting support and being given the generic frustrating answer: "Download the latest video drivers", which of course I was already using.
To fix my issue, I changed my video card settings to "Best Performance" (the lowest), and then cranked up the game to the best of everything. Works and looks great as well. Haven't had a problem since.
Even leaving my video settings that low hasn't had a negative effect on anything else, not that MY eyes can see at least. My AOM still looks great, which is my #1 priority. Well, make that #2 now that CotN is out......