Sounds like it is hanging when you exit and later try to restart Firefox. * How to stop the running Firefox process ** In Task Manager, does firefox.exe show in the '''<u>Processes</u>''' tab? ** See: http://kb.mozillazine.org/Kill_application **Windows 7 users: http://www.techrepublic.com/blog/window-on-windows/reap-the-benefits-of-windows-7s-task-manager/2576 * What may cause Firefox to hang at exit **Windows 7 Task Manager: http://www.techrepublic.com/blog/window-on-windows/reap-the-benefits-of-windows-7s-task-manager/2576 ** http://support.mozilla.com/en-US/kb/Firefox+hangs ** http://kb.mozillazine.org/Firefox_hangs ** https://support.mozilla.com/en-US/kb/Firefox+is+already+running+but+is+not+responding * You may need to try Firefox Safe Mode ** You may need to use '''Safe Mode''' to locate the problem: ***See: http://kb.mozillazine.org/Safe_Mode ***Firefox 4 users, hold the Shift key while clicking the Firefox 4 desktop icon to enter Safe Mode. ***Firefox Safe Mode is a diagnostic mode that disables Extensions and some other features of Firefox. ****In Firefox 4, Safe Mode also disables Plugins and Hardware Acceleration. ****If you are using a theme, switch to the DEFAULT theme: Tools > Add-ons > Themes '''<u>before</u>''' starting Safe Mode (In Firefox 4, Tools > Add-ons > Appearance). See: http://support.mozilla.com/en-US/kb/Using%20themes%20with%20Firefox#w_managing-themes-and-personas ****When entering Safe Mode, do not check any items on the entry window, just click "Continue in Safe Mode". ****Test to see if the problem you are experiencing is corrected. *** If the problem does not occur in Safe-mode then disable all of your Extensions and Plug-ins and then try to find which is causing it ***#by enabling '''<u>one at a time</u>''' until the problem reappears. ***#You can also enable a few at a time (3-5), keeping track of what you just re-enabled to see if the problem re-occurs; this will help narrow down the possibilities if you have a large number of add-ons. ***#'''<u>You MUST close and restart Firefox after EACH change</u>''' via File > Restart Firefox (on Mac: Firefox > Quit). ***#You can use "Disable all add-ons" on the Safe Mode start window. **See the following for more information *** http://support.mozilla.com/en-US/kb/Troubleshooting+extensions+and+themes *** http://support.mozilla.com/en-US/kb/Troubleshooting+plugins *** http://support.mozilla.com/en-US/kb/Basic+Troubleshooting <br /> -------------------------- <br /> '''You need to update the following.''' The Plugin version(s) shown below was/were submitted with your question and is/are out of date. You should update to avoid known security issues with the version(s) you have installed. Click on "More system info..." to the right of your question to see what was included with your question. *Shockwave Flash 10.1 r85 *Next Generation Java Plug-in 1.6.0_22 for Mozilla browsers #'''''Check your plugin versions''''' on either of the following links': #*http://www.mozilla.com/en-US/plugincheck/ #*https://www-trunk.stage.mozilla.com/en-US/plugincheck/ #*'''Note: plugin check page does not have information on all plugin versions''' #*There are plugin specific testing links available from this page: #**http://kb.mozillazine.org/Testing_plugins #'''Update the [[Managing the Flash plugin|Flash]] plugin''' to the latest version. #*Download and SAVE to your Desktop so you can find the installer later #*If you do not have the current version, click on the "Player Download Center" link on the "'''Download and information'''" or "'''Download Manual installers'''" below #*After download is complete, exit Firefox #*Click on the installer you just downloaded and install #**Windows 7 and Vista: may need to right-click the installer and choose "Run as Administrator" #*Start Firefox and check your version again or test the installation by going back to the download link below #*'''Download and information''': http://www.adobe.com/software/flash/about/ #**Use Firefox to go to the above site to update the Firefox plugin (will also install plugin for most other browsers; except IE) #**Use IE to go to the above site to update the IE ActiveX #*'''Download Manual installers'''. #**http://kb2.adobe.com/cps/191/tn_19166.html#main_ManualInstaller #**Note separate links for: #***Plugin for Firefox and most other browsers #***ActiveX for IE #'''Update the [[Java]] plugin''' to the latest version. #*Download site: http://www.oracle.com/technetwork/java/javase/downloads/index.html (Java Platform: Download JRE) #**'''''Be sure to <u>un-check the Yahoo Toolbar</u> option during the install if you do not want it installed. #*Also see "Manual Update" in this article to update from the Java Control Panel in Windows Control Panel: http://support.mozilla.com/en-US/kb/Using+the+Java+plugin+with+Firefox#Updates #* Removing old versions (if needed): http://www.java.com/en/download/faq/remove_olderversions.xml #* Remove multiple Java Console extensions (if needed): http://kb.mozillazine.org/Firefox_:_FAQs_:_Install_Java#Multiple_Java_Console_extensions #*Java Test: http://www.java.com/en/download/help/testvm.xml

Thank you for the help. I started to update the plug ins and noticed it was actually running at 50% of CPU just sitting on a static page. I have completely uninstalled and reinstalled firefox 4.0 twice now. Still does it. before any plugins are added. So, if I am sitting on a static webpage with everything loaded, and the CPU is still running at 50% tying up over 120mb of ram, then what? Haven't closed a session so it can't be hanging up on the close out.

Just keep following the suggested solution until you die.

I've done everything suggested...and "oddbodd's" reply seems to be the best solution yet.

I have this problem too.. Going to task manager/processes and ending the process works. Its a pain in the ass and I hope Mozilla fixes it soon. Not to metion it makes me wonder exactly WHAT Firefox is doing in there when its supposed to be OFF!! Its very disconcerting and am considering switching to chrome because of it.

Exactly!

If you just did a Java upgrade you need to go back to version 6. The current version of FireFox is not compatible with the latest Java release. If you havent upgraded yet... do so and follow the following steps: 1. Goto 'Control Panel' 2. Click on the 'Java' icon to display a menu 3. when the menu open click the 'Advanced' tab and then 'Default Java for Browsers' 4. The 'Mozilla Family check box will be unchecked. you need to check it. 5. click 'OK' at the bottom of the screen 6. reboot your computer 7. ENJOY! :D