Hello Juliet,
I used the FRST tool and the Delfix tool as you suggested. No problems.
As far as the audio/video sync problem, I have not been clear.
Youtube works perfectly. It is others that have streaming that has problems. CNN, NBC, Comcast sports, etc., are the ones out of sync.
I do not have Firefox and have never used it.
The Google support page seems to be for those who make their own videos. I do not. I do not have any of the editing programs it refers to.
Sorry if I confused you.
Happy Sunday,
Jerry