system
4
Problem Solved 
Nevisos, you are right, SP3 or maybe just SP2 must be installed before installing AVAST 6.0.1125.
I said in my first post “I will fully install ALL Windows updates before proceeding.” I did install all Windows updates before installing AVAST latest version. All is now well. Too bad I had to make so many XP installs. It seems there should be some warning about compatibility or at least Avast should detect if XP3 is installed and abort with a compatibility message. Hope someone is listening.