I've got a P4 2.4 gig machine with 256 megs of ram, running WinXP, and, once I patched to SR2.1 I've had very few problems. The hair dynamics are stable, and haven't crashed on me yet, though they can take quite some time to calculate, and tend to go flying in every direction when collisions are turned on. I still have the cloth room hang on me on rare occasions, but almost always its because I've tweaked a dynamics setting too low or too high (setting cloth density too high can cause problems). I simply save before I calculate any cloth dynamics, then, if it hangs, hit ctrl-alt-del and exit Poser 5. Afterwards, I re-open Poser, reload the project, and adjust the offending dynamics dial before recalculating the dynamics. As for systems, I hope your new PC has a ton of memory. My 256 megs isn't nearly enough, as Poser regularly is forced to using the full volume of my swap file (especially when rendering strand-based hair on larger graphics at higher dpi settings). I'm glad I've got a fast hard disk drive. I've got a friend who's got an older PC, with only 128 megs of ram, and Poser 5 just laughs at him when he tries to use the cloth or hair rooms.