Emily you have my sympathy, I have a 3yo HP pavilion on Win98 that really struggles with Poser despite upgrading to 146meg ram and a 20 gig HD. Most times I have to save a drawing then reboot the PC before rendering or risk a freeze from Poser due to exhausting the ram. Tonight I picked up a tip from the Daz faq tech board, downloaded and installed Cacheman memory manager from ZDnet. Let the wizards optimise the settings, so far so good! ,Poser is working faster, done several multi figure renders and no freezes, even web pages are much faster opening despite 2 programs and a download all happening right now (really pushing my luck!) Next test is windows media player which often crashes my system. This info may not help you on XP but other users with underpowered systems like mine have nothing to lose by trying Cacheman.
Tommy.