This has happened to me enough times with various versions of Poser that I have learned to always save before rendering. If the render crashses (gets stuck) then things often get really scrambled. If you have another saved version (I also tend to save more than one copy of each project in case I decide to go back to an earlier pose, light setting, etc.), then your best bet is to close Poser to unscramble it's "brain", then restart it and open your document again. This seems to happen to me most oftyen when either I'm using a lot of different textures or have tried a lot of textures (so they are still in Poser memory).