I guess this is a virus or hijack program. I have now Firefox 18.0.2 installed. The problem is: no URL is loaded, Firefox doesn't show any warning, just a blank page. If I enter an URL in the address bar, it loads for a very short time (too short), but it just opens an 'about:blank' page.
I have reinstalled, deleted all browser history, restored the factory settings, entered safe mode,.. But still the same. It might be something in the registry, but I have no clue as where to look.
Did anyone encounter something similar?