Ever since installing Internet Explorer 9, several my games in Steam either crash (for instance Burnout Paradise) or insist on minimizing to the task bar (for instance GTA IV). In the latter case, they seem to be running, but it appears some other window is stealing focus, essentially switching out of the game.
I'm on Windows Vista Business with SP2 and use Microsoft Security Essentials and have the exact same behavior on my Windows 7 Professional with SP1 laptop. There's nothing noteworthy installed or running while launching a game from Steam.
I recall reading that IE9 installs a new version of DirectX, so perhaps this is causing problems. Is this a known problem and is there a solution, or am I wrong about this?