i Have XP Pro and i installed poser 5. it crashed and froze somany times i just went back to poser pro. Its not XP. Not that im very fond of microsoft either. my boyfriend runs some high end 3d apps on this computer and has never had a problem till poser 5. its pretty sad when you have a dual processor computer with 5 gigs of ram and it crashes because of poorly writen software.Oh and if someone from Curious labs reads this yes i had all the service packs. You people need to get the bugs out so i can take my poser 5 disk out of its current retirement as a coffee cup coaster.