Things not working after Live Update

Hi guys

I have done a live update on 29 july, and since then my sound control doesn't work properly anymore. Means, I can still regulate sound with the mouse, but not with the keyboard anymore (just don't get any reaction).

Then I've got an older problem from the live update from 15 avril: everything webcam/ video related stopped working. I cannot show any kind of videos (e.g. mpg or mov) on my computer (except online), and I've tried many different programmes without success. And my webcam doesn't show any picture anymore most of the time, there's just a grey screen.

Does anyone know how to fix those problems? I could post a list with the names/ numbers of the updates, if this is helpful.
And shall I stop making live updates at all? Seems to me they only cause troubles and are good for nothing.