I recently did a round of updates to my 2009 C2D iMac and now every video file I play has it's audio out of sync. Doesn't matter if it is flash-based, Quicktime, MKV, etc. they are all off. Oddly, restarting the computer fixes it, but if I use the computer for anything else before I watch a video it will go back out of sync. I have re-installed Adobe Flash. I'm running 10.7.5. Can anyone help?