I have installed Windows 8.1 64 Bit and i am using IE 11 and flasplayer version 11.9.900.170.
All updates from Microsoft are installed.
Flashplayer videos are not displayed. If i switch to compatiblity mode in IE 11, the videos are displayed correct.
The tests of flashplayer with adobe website delivers different results as follows:
This is a known problem with Internet Explorer 11, which Microsoft has been aware of since October 18 when they released their latest "untested" browser. The pages can't recognize the browser, so they don't recognize any of the plugins, like Flash Player. So far, Microsoft has made NO indication that they have any plan to fix it soon.
Microsoft's recommendation (as you've seen) is to use Compatibility View for affected pages, and "pretend" you're using an different browser. Trouble with that is it has seen limited success at best, and you have to individually enable it for EVERY page that has problems.
I'm not big on "pretending" so I recommend actually using another browser.
ANY of those will work where IE11 won't, with the Flash Player Plug-in (For all other browsers), and Chrome doesn't even need that because it has its own Flash Player plugin built in.