Do the following please.

Click the orange Firefox button, go to Add-ons, then Plugins.

• Disable Macromedia Shockwave for Director
• Disable BrowserPlus

Next, update the following:

• Java via http://www.java.com/en/
• Flash via http://get.adobe.com/flashplayer/
• Adobe Shockwave For Director via http://get.adobe.com/shockwave/

Some others to check.

• Microsoft Silverlight, update via the Windows Update site. "Silverlight" is Microsoft's version of Flash used by an increasing number of sites. You don't appear to have it installed at all.
• Quicktime via http://www.apple.com/quicktime/download/ (only necessary if your version is older than v7.6.9)

Macromedia was acquired by Adobe some time ago. The "Macromedia Shockwave For Director" which you have installed is obsolete now and has been replaced by the Adobe version. You have the Adobe version installed as well, but it's out of date, hence the link to update it above.

Your Flash player is not only out of date, but also a security risk. See http://www.adobe.com/support/security/advisories/apsa11-02.html

Thank you, It seams the problem have solved. I was able to watch video on youtube for the first time on Firefox since long time! Hope it will continue!

You're welcome.

Could you please click the "Solved It" button to take your post out of the loop?

Thanks.