Poser 4 or 5? Did you recently update OpenGL? (The latest update's a bit wonky, but if you haven't changed it, I doubt it would just start causing a problem now. If it's Poser 5, I'd recommend updating to SR-4 if you haven't already... besides that, I can't think of any reason that it would just decide to start getting silly one day. What about system RAM? Is anything else (such as Mackafee or Norton) chewing up local memory?