Youtube stops loading videos at random

Hey all. Run into a hiccup recently that I'm finding rather infuriating.

As of about a week ago, seemingly at random, videos on Youtube will simply stop loading, usually somewhere around the 2-minute mark of playback. It stops spooling and then sits forever on the loading spinny thing.

Firefox and Flash Player are fully updated, I haven't changed any addon settings, nor has my ISP done anything different, and nothing on the Youtube pages themselves is blocked by AdBlock or NoScript. FF purges its own temp files on every close. I've manually dumped my cache and cookies multiple times. Reloading the video doesn't help (even control-refreshing), closing Firefox doesn't help, and there are some videos that I first noticed this on that -still- won't play a week later - and I shut my PC down completely on a nightly basis.

What really kills me is that there is no rhyme or reason to what videos glitch out - three minutes long or thirty, any number of channels or posters, even within the same playlist (one video refuses to play, the previous and next do just fine). Youtube and Google's own help is completely useless on this - anyone at all have a clue?

 

Most likely it is Shockwave or Flash Player causing the issue try uninstalling them and reinstalling with the latest version

 

XP as noted in my sig; DL speed and chkdsk come back fine; any time of day; it's YouTube proper; Avast, fully updated; I run MalwareBytes on a regular basis.

I'm up to date on FLash Player, but I hadn't checked Shockwave itself. Will have a look.

 

You can test this really easily by going into Youtube options and switching to HTML5 for playing video.

 

Fair enough. I'm apparently blind though, where exactly is that?

 

Great question. They seemed to have removed the option in settings.

I did find this though:

https://addons.mozilla.org/en-US/firefox/addon/youtube-all-html5/

 

On Youtube, I believe you can choose HTML5 for playing videos on this page:
http://www.youtube.com/html5

 

A brief followup - I tried switching to the HTML5 player, and though I had to tinker with my Adblock/Noscript settings, things appear to have improved somewhat. I will cautiously say that I haven't -yet- hit a video that isn't available in the HTML5 player, though I've only tested a handful, and it actually seems to spool an entire video like the site used to.