It's happened to me a couple times on update, I think even on Vista, but not every time. I had 7 just lose visual effects on its own, and then come back on its own less than a minute later. Dunno. At least you know what to do if it happens again...of course next time it'll be something different.

Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris