Windowed games "flashing"

Almost every game I play with window mode, in a short time starts to randomly "flashing", its like a very fast alt+tab.
That happens alot in World of Warcraft, Dragon Age Origins and even on Firefox.
This can be "solved" changing to "Wndows XP SP3" compatible mode, you solve this but get another problem, like connection lag, crashes, etc.

As far i remember since pre-beta I have this problem. I'm with RTM now, updated drivers, updated games and programs.

Any clues?

I have the exact same problem, it really is annoying. I didn't know about that "solution" you mentioned though, that might relieve the frustration for now..

Hopefully it won't crash too often.

(pardon me if this is a necropost, found the thread through a Google search)