well pretty much during you're installation you have to click activate later, then you have to put that MF.dll in you're halo 2 root folder, but apparently the LIVE option was still greyed out. So then you had to manually install LIVE and the c++ distributable off either the DVD or the iso. But then this guy figured out that if you have a product ID in the registry then the LIVE option would be enabled. So you'd need to actually have a purchased game or acquire a product ID from someone...

I'm not sure about xp 64bit, i don't think it was ever supported for it.