windows messenger does not, I repeat DOES NOT cause pop ups, you are getting advertisements pop ups that are being sent using Messenger Service which is NOT APART OF MSN Messanger....while surfing the internet of you get a window that is being used my Internet explorer, that is a pop up, the other is called a Net Send. To disable net send pop ups do as I posted before. No software will stop net sends, only turning off the service will. I hope everyone understands now