Quote - 1. There is no window after trying to open files

2. When I click OK Poser opens with no window at all
3. If I change window size it makes no difference

Go to the Edit menu option and set your preferences to open at Factory Default.

Then close poser, and reopen it again. It should be the way it was initially installed.

Then set up the interface the way you want it again, then go back to your Edit menu and set your preferences to "preferred".

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi