Thank you for your open words.
I discussed with my team and did the repair installation today with some reboots and over 200 updates. IE9 was fixed instantly, IE10 update just went through.
Thank you for all the effort - I learnt a lot in the process but I believe this was the best to do in the end, I did not want to waste anymore of your time in this complictated server.
I still wonder how it came so far but I am very happy that it works now.
kind regards,
Thomas.