Why do I get the error "Your browser does not recognise any of video formats available" ONLY ON YouTube and embeded videos + very few ads ?

If i enter a video (through YT search for example) it might show it directly but not always.Also if i move to other video from that,i can see that one directly (exept music videos.I guess bc they are in "music" category) and i can also see the original video if i click back . If i enter a video through... show more If i enter a video (through YT search for example) it might show it directly but not always.Also if i move to other video from that,i can see that one directly (exept music videos.I guess bc they are in "music" category) and i can also see the original video if i click back .
If i enter a video through google search,i also need to do this forward and back move to see it.
It was fine until 1-2 weeks ago,then,over day,it suddenly stopped working.


I have windows XP and won't change it for anything,i also have Firefox 42 and won't change it,except maybe only some few numbers up,as i don't like the latest design of it.




Why do i get this error and how do i fix it ?
2 answers 2