How do you switch to flash player on browser? Both IE and FF on my new Dell XPS 8700 with Windows 8.1 struggle with all video play back from YouTube, Vimeo. But, watching Hulu, Netflix works great. As near as I can tell it's the browsers default to HTML.
If I watch the same YouTube video on another system with Flashplayer, the video is fine. But on my desktop, audio and video are out of sync and the video stops every 20 seconds.