I used to have that problem constantly on WIN98. I recently set up a dual-boot with Win2K and only rarely have a memory related problem with Poser. While i was still having the problem I looked into the issue here in the forums and found that nearly everyone with the same problem was on win98 (which almost everyone I know that deals with software told me has a ton of memory issues) so yes an upgrade or at least a dual boot set up would be the best.