YouTube videos won't play in Firefox?

[Inferno.]

Earlier on today my mam was all "the laptop won't play a YouTube video " so I messed on with it a bit (restarting Firefox, restarting the laptop. Nothing.)

So I ended up formatting my laptop and installing 64bit Windows 7 (was 32bit), re-installed all my programs etc but Firefox is refusing to play a flash video, I just get a black screen with nothing on it. I googled it but came across nothing of use.

Videos play fine on my laptop through Opera, so it's got to be a problem with Firefox.

Anyone else having the same problem or have a solution?

[Rasgrez]

Odd. I've never had that problem before while running FF. Currently on version 3.6.18.

[Nemkoon]

I have this Problem with IE, except for embedded videos..
I found out that the play videos on webpages, wasn't in the advanced options, like it should be.
Also, make sure your flash is updated. Most likely that, even though in the middle of the black screen, it's supposed to say Needs adobe flash player version ______

[Inferno.]

I have Firefox 5.0 if it matters.

I already have the latest version of Flash player installed.

[Nemkoon]

Weird....

[Supreme Warrior]

I also have Firefox 5.0 and youtube runs perfectly, only prob I had was Firefoxs famous Memory leak which I somehow fixed when I cleared the cookies and cache.

seems the Firefox team is getting lazy, you might want to report this error on Bugzilla.

[Inferno.]

I don't understand why it would happen on two separate computers though?

[Fer!]

I was hearing earlier about some computers having trouble with Youtube and some browsers working or not, I'm guessing it's an issue on their end.

[Inferno.]

Actually judging by how YouTube looks in Opera now they're doing loads of changes to the video player interface, that's probably why it's not working right in Firefox right now.

[Knightshade]

I had this problem a little while back in firefox I found a fix that worked for me try right clicking on the video going to settings and making sure hardware acceleration is not enabled this problem only happens in firefox with youtube all other video sites should be fine.

[Inferno.]

YouTube is working fine in Firefox again for me now. I guess I should lock this.