hmm.. I don't know what to say... continued my search for a solution to the problem and my browser landed at this adress:
http://www.annoyances.org/exec/show/article04-107
when I followed the instructions and my computer had completed the reboot I couldn't believe my eyes.. msn, windows update and all the former blocked sites was again availible... one little registry entry could cause so much harm here... must check the other computers in the network for spyware now I guess..
thanks anyway for trying to help me.. let's hope this will help some others maybe having the same problem
//Micke