hi supreme moderator ;-) thanks for your answer,
no kasperky or anti-Hacker in my computer, only kerio firewall and mcafee virusscan that i have uninstalled but i still have the same pb.
i think it's because of the program update (avast home 4.1.289 to 4.1.319) because it's ok again now with the 4.1.289 i have reinstalled.
So for the moment, i will just update IAVS and will install a second antivirus which doesn't conflict with avast.. do u think it is a good idea? are there many people having pb with this pgm update?