If you have automatic updates set, it WILL be forced on you, soon.
This might help:
As, of course, will disabling automatic updates.
What???? Even if you run Linux??????
I have noticed that in the restore menu there is an option to restore to windows 7. I wonder if that would restore the games, too?
It should restore it to it's pre-upgrade state.
Mine did, too, much to my surprise.