Could it be that it opens up off screen (for example if you're on a laptop and have been connected to a second monitor or projector)?
Try launching the Edit Script dialog (Ctrl + E), then hit Alt + Space, then M (for move) and finally try using the arrow keys to see if you can guide the window back to your screen view.
Is the freezing an actual freezing or is it because the modal script editor is open? When it "freezes", if you hit esc (closing script editor), does QlikView come back alive?
