This may not be typical, but I had some problems installing the OS on my system. I had a 32-bit copy of XP (full edition) and the Vista Ultimate upgrade. Because Vista was an upgrade, I had to install XP first and then, once XP was running, install Vista from there. Because my system had 8 GB of RAM installed, XP simply would not install. It would get to a certain point and fail. I spent over a day trying to figure out what happened. I finally had to take out some memory until I had 2 GB (I had four 2GB dims) and then XP would install. So you may want to leave out some of your memory (if you get more than 3 GB) while initially installing XP.