Wow, That sounds nasty. I hate to say it, but I'd guess the problem to be a bad graphics card. I have nothing like this with mine: G5 2x2GHz 2.5 Gigs RAM ATI graphics OXS 10.3.5 Poser 5 SR4 If your machine is new, then that is where I'd check first with your local genius. They will hopefully have a less crappy idea, but unless I'm mistaken, a bum card could be responsible for both problems....