We have tried disabling all anti-virus, anti-spam, and firewall programs.

That did not help. And also customers all had different programs.

I have been suspecting some automatic update of something from Microsoft because the programs did work and now they do not.

Am adding all updates from last 2 years to a laptop similarly configured... in groups of 10 trying to see if I can narrow down one of the updates as a culprit.

The program is a VB6 program and does not use C++.

Doing some logging would be good.... I would have to do that manually in VB6 or were you referring to some function of setupbuilder....