I also am experiencing this since I downloaded Windows 8.1 with Internet Explorer 11 (originally had W8).
I have the latest Adobe Flash Player installed per Adobe's website verifying it.
Since the W8.1 update I can no longer view many online videos and tv sites that I previously were able to with no problem.
I am discovering many people are discovering this problem after they download the W8.1 upgrade.
Flash Player is preinstalled on Internet Explorer on Windows 8.x.
If you deleted/uninstalled it, you need to download it from Microsoft (not Adobe).
...you need to download it from Microsoft (not Adobe).
I deleted the version I downloaded from Adobe, then restarted the computer.
Next I tried to find Adobe Flash at Microsoft but I can only find the updates for it and when I attempted to download 1 it said I already have it (the update). This occurred at thre Microsoft download Center.
Where specifically might I get the Microsoft version of Adobe or how do I get it would be helpful at this point.
Thanx for the help.