I DON'T KNOW BUT IF YOU CAN FIGURE IT OUT MAKE SURE YOU BACKUP EVERYTHING YOU NEED SO YOU CAN PUT IT BACK ON XP VERSION, I'M STILL TRYING TO FIGURE OUT HOW TO UPDATE TO WINXP 64BIT WITHOUT LOSES ALL MY INFO
There are plenty of hacks to play Halo 2 on XP, but none of them allow a proper connection to Live (and you cannot register the game, which means you have to crack the activation, and there's no online play). Since there is no proper connection to Live, you also get hit with that annoying message explaining that you are not on the same level that Live says you are, and you'll see it at the beginning of every level (and often in the middle of cutscenes, which completely messes them up).
I'm curious about the aforementioned patch from Microsoft that allows playing on XP. I cannot find anything like it, so