download fresh installer from here and try * getfirefox.com

That's exactly what I download and after running still got "Your computer must be restarted to complete a previous update of Firefox. Do you want to reboot now?" If I click No. Setup just exit. If I click Yes, computer reboots and I'm in square one again.

Remove the Firefox program folder (C:\Program Files\Mozilla Firefox\) before installing that newly downloaded copy of the Firefox installer. * It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling. Your bookmarks and other profile data are stored elsewhere in the Firefox Profile Folder and won't be affected by a reinstall, but make sure that you do not select to remove personal data if you uninstall Firefox. * http://kb.mozillazine.org/Profile_folder_-_Firefox * http://kb.mozillazine.org/Profile_backup

Sounds like Firefox is "hanging at exit". That problem is frequently caused by an Extension or a Plugin. Read all of the following articles.<br /><br /> Note: *You must wait a few seconds (10-30) after closing Firefox to allow it time to completely shut down all processes. *'''''ALWAYS''''' use Firefox button > Exit (or File > Exit) to close Firefox properly; avoid using the "X" close button in the upper right corner. #Stop the Firefox process: #*[http://kb.mozillazine.org/Kill_application Mozillazine - Kill application] #*Windows 7 users click [http://www.techrepublic.com/blog/window-on-windows/reap-the-benefits-of-windows-7s-task-manager/2576 here] #*Mac users: http://techheavy.com/2011/02/the-mac-task-manager/ #Why Firefox may hang: #*[http://support.mozilla.com/en-US/kb/Firefox+hangs Firefox hangs] (see Hang at exit) #*[http://kb.mozillazine.org/Firefox_hangs Firefox hangs (Mozillazine)] (see Hang at exit and Closing Firefox properly) #*[https://support.mozilla.com/en-US/kb/Firefox+is+already+running+but+is+not+responding Firefox is already running but is not responding] #Use Firefox Safe Mode to find a problem with an Extension or Plugin: #*Don't check anything when entering Safe Mode, just continue #*If the problem does not occur in Safe Mode it is probably and Extension or Plugin causing the problem #*See: #**[[Safe Mode]] and [http://kb.mozillazine.org/Safe_Mode Safe Mode (Mozillazine)] #**[http://support.mozilla.com/en-US/kb/Troubleshooting+extensions+and+themes Troubleshooting extensions and themes] #**[http://support.mozilla.com/en-US/kb/Troubleshooting+plugins Troubleshooting plugins] #**[http://support.mozilla.com/en-US/kb/Basic+Troubleshooting Basic Troubleshooting] '''If this reply solves your problem, please click "Solved It" next to this reply when <u>signed-in</u> to the forum.''' ------------------------- Not related to your question, but... You may need to update some plug-ins. Check your plug-ins and update as necessary: *Plug-in check --> http://www.mozilla.org/en-US/plugincheck/ *Adobe Shockwave for Director Netscape plug-in: [https://support.mozilla.com/en-US/kb/Using%20the%20Shockwave%20plugin%20with%20Firefox#w_installing-shockwave Installing ('''''or Updating''''') the Shockwave plugin with Firefox] *Adobe PDF Plug-In For Firefox and Netscape: [https://support.mozilla.com/en-US/kb/Using%20the%20Adobe%20Reader%20plugin%20with%20Firefox#w_installing-and-updating-adobe-reader Installing/Updating Adobe Reader in Firefox] *Shockwave Flash (Adobe Flash or Flash): [https://support.mozilla.com/en-US/kb/Managing%20the%20Flash%20plugin#w_updating-flash Updating Flash in Firefox] *Next Generation Java Plug-in for Mozilla browsers: [https://support.mozilla.com/en-US/kb/Using%20the%20Java%20plugin%20with%20Firefox#w_installing-or-updating-java Installing or Updating Java in Firefox]