Vista Games Font Problem - Joebug

I have been using Vista for a couple of months.
Recently I encountered a problem with Vista games.  The games (Mahjong
Titans; Minesweeper etc) have lost their fonts.  Titles  and tips have now
very large fonts which do not fit in game screens/pop up tips.
I would appreciate if I can get help to get the original fonts back.
I am using the latest Nvidia drivers for my system (GeForce 7800GTX SLI)

Thanks