What is a “program group”?
A program group is actually what it sounds like, a group of programs that are (usually) related. Normally, it’s one main program, an uninstall program, and maybe a utility or two.
When you hit Start>AllPrograms, all those little icons you see are program groups. Depending on the version of Windows you’re running they might have arrows next to them or just drop down when you click on an icon.
In the image below, the red box is around items that are program groups.
For the most part, every time you install a new program, you get a new program group.