Plugin_container.exe works like a kind of sandbox to isolate plugins like Adobe Flash when they crash. This prevents the whole browser crashing.

Try updating to the latest version of Flash which is 10.2.159.1 from http://get.adobe.com/flashplayer/

To ensure a clean installation, I would recommend you uninstall the existing version using Adobe's tool called uninstall_flash_player.exe which you can download from here: http://kb2.adobe.com/cps/141/tn_14157.html

Close Firefox before you run it and then reboot.

Then either run the new version you downloaded earlier, or go to the same site again and install it from there.

Thank you for the help. I did what you suggested but nothing changed. i'm thinking of a complete unistall of firefox and after that i'll make a clean installation...!

That can sometimes be a good solution. To make sure it installs correctly, please follow these steps.

• Go to Download Firefox 4.0 and download a fresh installation file to the desktop. If necessary, download the file with IE8 or 9 and choose to save it to your desktop when you see the prompt.

• Then go to Add/Remove Programs, scroll down to Mozilla Firefox and remove it, choosing to keep your bookmarks, customizations etc., (don't checkmark the box).

• Then reboot and delete the folder called Mozilla Firefox at this location: C:\Program Files\Mozilla Firefox

• Finally run the installation file you downloaded to the desktop earlier.

NO.......! Nothing happened! The same problem.

Sorry to hear that.

Try creating a new profile since the new installation still uses the old one. See Profile Manager - Create, remove or switch Firefox profiles

I will try your suggestion but i think that there is a problem caused by the adobe flash player, so the companies' developers might give the solution.. soon, i hope!