Hi Ciorsten. Youre up late too? Its a nightmare your problem but dont worry. Interupt the normal boot up by pressing the F8 key.
Then go through the steps when asked, but select the VGA Safe mode. I think that should restore the old VGA driver as default.
This is sufficient for you to work and roll back the driver and select the correct one. I am not 100% on this but try it as you cant hurt anything. (more)
Let me know if you have any problems, Im here too!! Kefty