Flashplayer not working in firefox

[DEL 707]

Had a problem for about the past 2 days where I can't watch anything on youtube, it keeps complaining about needing a flashplayer update, which I've run several times but it doesn't make a difference.
I've also tried uninstalling and reinstalling the plugin, but I get the same results.

I've just tried it it IE and it works fine.

Anyone know of any solutions?

 

[DEL 707]

I'm running standard 32bit XP pro

 

[DEL 707]

Think I've found the problem.
I'm running the noscript addon and on youtube it's set to forbid ytimg.com, I temporarily allowed it and it played a video.

I don't remember ytimg.com, as i said youtube has worked fine before. Is ytimg safe to allow?