Video in 8.1

I installed a new system - it was 7, now 8.1. And such garbage happened - any video that I want to watch on the net starts and goes. BUT - as soon as I open it to full screen, it stops, and the sound continues to go. I do it on the back , is played. Already I installed a bunch of different codecs. Not in any. Only YouTube plows without problems when I do everything. In general, it writes in VK, the video file has not yet loaded and is stupid. Who knows what kind of heresy? Previously, there was 8.1 of this did not have.