disable windows games

That should be possible under:
User policies --> policies --> Administrative Templates --> system --> find the policy named "don't run specified Windows Applications"
add:

hearts.exe

freecell.exe

inkball.exe

winmine.exe

mahjong.exe

Pinball.exe

solitaire.exe

SpiderSolitaire.exe

PurblePlace.exe

sol.exe

minesweeper.exe

spider.exe

mshearts.exe

chess.exe

Please be aware that i don't know if there has been added any further games since i made that list and that the users can workaround this block by finding the .exe files and change the filename to something different.