I have Windows 7, and have not run into that. Can you undo the update? Or was it one with a gazillion updates? In that case, a system restore would be my next step. Assuming no other answers are forthcoming here.
Another thought I just had: Windows may have installed and activated its own audio drivers. If so, you want to disable those. these can come with your video card also, so check that out as well. windows likes to do your thinking for you. It's the Nanny State of operating systems.