Open My Computer - click on "uninstall or change a program" - on the left, click "turn windows features on or off" - uncheck games - hit ok, and let windows do its business - restart the computer and go back to this area and re-check games - once again let windows do its business and restart - your games should be functional again.
What antivirus are you using- i don't think an antivirus would corrupt windows games - perhaps it was something else - or a virus got to some windows files including those of the games and the antivirus then removed some of the game files.