The symptoms certain suggest something with OpenGl.
Have you tried setting your display mode to Sreed?
Sometimes mystery problems are solved by deleting "poser.ini" and letting it generate a new one
Sometime when I have what might be a texture problem, I temporarily rename the texture folder and set search depth to none.
When it asks if I want to look, I say no and it will load without textures.  Then I can add them singly