Firefox 6.0 is still in BETA and not slated for release until August 16.

To resolve the problem, click the following link to download the current version: Firefox 5.0.1 then proceed as follows:

1. Uninstall the version you have at the moment via "Programs and Features" in Control Panel choosing to keep your bookmarks, customizations etc., (don't checkmark the box).
   
   
2. Next, reboot.
   
   
3. When the system boots to the desktop, delete the folder called "Mozilla Firefox" at this location: C:\Program Files\
   
   
4. Run the installation file you downloaded earlier.
   

Your bookmarks, customizations etc., are maintained in a different location and will become available to you again once you complete the installation.

As a precaution though, it's always advisable to have a backup copy of your Bookmarks. To make one, do the following:

1. Click the orange Firefox button, go to Bookmarks, then Show All Bookmarks to open the Bookmarks Manager.
   
   
2. Click the link to Import and Backup and then click Export HTML and save the file somewhere.

You can use the same Bookmarks Manager to import the file you saved by choosing "Import HTML" should that prove to be necessary.

I changed from 6.0, but the firefox plugin still malfunctions;works a few hrs, then goes out

I have no problem whatsoever with Youtube or any other video site for that matter. I even maintain a channel on YT: http://www.youtube.com/user/Xircal

I wouldn't be able to do that if Firefox didn't work properly.

What I suggest you do initially is to click the orange Firefox button, go to Add-ons, then Plugins.

In there, disable the following:

• Yahoo BrowserPlus
  
  
• Yahoo Application State Plugin version 1.0.0.7
  
  

If the problem persists, run Firefox in Diagnose Firefox issues using Troubleshoot Mode. If it functions properly in that configuration, then one of your add-ons is the culprit.

See also: http://kb.mozillazine.org/Flash#Performance_or_display_issues_with_certain_Flash_videos

Make sure that you allow the plugin-container process in the firewall with full internet access.