Okay, so it does not appear to be a problem with the Poser installation, or with your video card, is what you seem to be saying.

It might just be a memory problem (unless you also run other applications that  use as much memory as Poser and they work fine). To eliminate this possibility you can run the Windows memory diagnostic utility. You will need to download this from the Microsoft web site and create a bootup CD. 

The only other thing I can suggest is to think back to what you changed just before it started playing up, and try to undo it... perhaps by going back to a System Restore point from before it started misbehaving. You do have System Restore points.... don't you? :O)

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)