It sounds to me like the installation went pear-shaped somewhere along the line. What I suggest you do is to do a new installation as follows: Go to [http://www.mozilla.com/en-US/firefox/fx/?ref=logo Download Firefox 4.0] and download a fresh installation file to the desktop. 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. After you complete the installation, go to the [http://www.mozilla.com/en-US/plugincheck/ Plugins Check] page and update those. In that respect, I notice that several of them are out of date which potentially exposes your system to attack. P.S. ''Sorry it took so long to respond to your question''.

If you wish to make Firefox 4 look like Firefox 3 go here http://www.askvg.com/how-to-make-mozilla-firefox-4-0-look-like-firefox-3-0/ Also use this addon https://addons.mozilla.org/en-US/firefox/addon/backforward-dropmarker/ Here is a theme (https://addons.mozilla.org/en-us/firefox/addon/firefox-3-theme-for-firefox/) which I have not tested but it seems good.