Please click '''Help '''| '''Check For Updates'''. If that doesn't work, please do the following.<br><br> #Click this direct download link to download the latest version: [http://www.mozilla.com/products/download.html?product=firefox-4.0.1&os=win&lang=en-US Download Firefox 4.0.1] The file looks the same as the one you see in the screenshot.<br><br> #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'').<br><br> #Then reboot and delete the folder called "Mozilla Firefox" at this location: C:\Program Files\Mozilla Firefox<br><br> #Finally run the installation file you downloaded to the desktop earlier.<br> Your bookmarks, customizations etc., are maintained in a different location and will become available to you again once you complete the installation.<br><br> ---- After you complete the installation, please go to the [http://www.mozilla.com/en-US/plugincheck/ Plugins Check] page and update where necessary.