I just tried to install Firefox 12 and the install will not proceed because it thinks that the old Firefox browser is open when it is not.

Question

I verified with Task Manager that Firefox is not running. How do I get past this point and get Firefox 12 to install. I am running Windows 7 Premium on an HP Quadcore with 8gb. of main memory, lots of video memory and 1tb of disk storage.

Answer 1

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: Establish a habit of exiting/closing Firefox with Firefox button > Exit or File > Exit to allow an orderly shutdown of Firefox and closing of all of the files that Firefox has open.
#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.org/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.org/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 an Extension or Plugin causing the problem
#*See:
#**[[Safe Mode]] and [http://kb.mozillazine.org/Safe_Mode Safe Mode (Mozillazine)]
#**[http://support.mozilla.org/en-US/kb/Troubleshooting+extensions+and+themes Troubleshooting extensions and themes]
#**[http://support.mozilla.org/en-US/kb/Troubleshooting+plugins Troubleshooting plugins]
#**[http://support.mozilla.org/en-US/kb/Basic+Troubleshooting Basic Troubleshooting]
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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.org/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.org/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.org/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.org/en-US/kb/Using%20the%20Java%20plugin%20with%20Firefox#w_installing-or-updating-java Installing or Updating Java in Firefox]