I just performed an "Update" (repair) to Win XP Home and the Messenger Service pop-us have started again.
Until now, I blocked these using my Firewall. I see that the settings are still intact, so something changed when I updated Win XP.
I checked Microsoft's site and they have advice on this. A solution is to disable the Service however, they also say if you do this that:
"Your antivirus program may use the Messenger service to send you notifications"
Anyone know if it will interfere with aVast? (I have v4.1)