If a game requires DIV 11, an d it is not on your system , it will normally prompt you to load it, the same as any game as any other program that requires (e.g. Flash Player).
I assume you are going to do other things apart from games, so I would suggest an office program like Open Office link text. As you are used to Exporer 8, stick with it (unless 9 is pre-installed) until you find your way around the new system.
Older games-- There is a compatabiity option, however I do not know the Windows 7 system enough to advise.