What to do to be able to watch videos again? Shockwave crash

Dear All,

I hadn't updated anything manually these days, but still, since yeterday, I am unable to watch any videos or listen to audios on websites, let the browser be Firefox, Opera, Chrome or Internet Explorer.

So I uninstalled and reinstalled the browsers in vain; uninstalled and reinstalled Shockwave, also in vain. The videos/audios don't even start playing, and I get the message that Shockwave crashed, or the plug-in doesn't respond, or the page is unresponsive. I tried <always activate>, <never activate>, <activate with permission> in Chrome and Firefox, but the problem persists, so I didn't continue with the other browsers.

No virus was found on the computer.

I have no idea what to do, could you, please, be so kind as to help me solve this? Thank you!

Windows 8.1, 64 bits

FIrefox 44.0.2  < Shockwave Flash 20.0.0.306  -updated 6th March 2016

G. Chrome 48.0.2564.116m    < same Shockwave Flash version as above