Please do the following.<br><br> #Use IE8 or IE9 to [http://www.mozilla.com/en-US/firefox/fx/?ref=logo Download Firefox 4.0.1] and save it to your desktop (''do not use the "Run" option'').<br><br> #If you have an earlier version of Firefox installed already, remove that in Add/Remove Programs choosing to keep your bookmarks, customizations etc., (don't checkmark the box).<br><br> #Next, 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><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> ---- If you've never had Firefox on your system before, then you can skip steps 2 & 3. ---- To import data from another browser please read this article: [[Importing bookmarks and other data from other browsers]]