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Firefox won't open, it won't even show me an error message, it's unresponsive.

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I was running firefox, then I clicked on a new webpage and it would not load. So I closed it firefox all together and tried to restart, but I kept getting the error message that it was already running (when it wasn't). I opened my Task Manager and saw that it was not running. So I restarted my computer and reopened firefox. It opened and ran for about 5 minutes before it wouldn't load a webpage again. So I went through the steps again, restarting my computer, only this time firefox would not open at all.

This happened

Not sure how often

This just started

User Agent

Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.30729; .NET CLR 3.0.30729)

I was running firefox, then I clicked on a new webpage and it would not load. So I closed it firefox all together and tried to restart, but I kept getting the error message that it was already running (when it wasn't). I opened my Task Manager and saw that it was not running. So I restarted my computer and reopened firefox. It opened and ran for about 5 minutes before it wouldn't load a webpage again. So I went through the steps again, restarting my computer, only this time firefox would not open at all. == This happened == Not sure how often == This just started == == User Agent == Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.30729; .NET CLR 3.0.30729)

All Replies (3)

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It looks like the lock file is still there, you would have to delete it. So you atleast dont have to restart your PC again. http://firefox.wont-open.com

However the reason why the lockfile doesnt get deleted automatically i dont know.

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Kill Application In Task Manager, does firefox.exe show in the Processes tab? See: Kill Application

Causes and solutions for Firefox hanging at exit: Firefox hangs or is not responding - How to fix Firefox hangs at exit "Firefox is already running but is not responding" error - How to fix

Safe Mode You may need to use Diagnose Firefox issues using Troubleshoot Mode (click on "Safe Mode" and read) to localize the problem. Firefox Safe Mode is a diagnostic mode that disables Extensions and some other features of Firefox. If you are using a theme, switch to the DEFAULT theme: Tools > Add-ons > Themes before starting Safe Mode. 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.

See: Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems Troubleshoot and diagnose Firefox problems

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 one at a time until the problem reappears. You MUST close and restart Firefox after EACH change via File > Restart Firefox (on Mac: Firefox > Quit). You can use "Disable all add-ons" on the Safe mode start window.

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Which security software (firewall) do you have?

See http://kb.mozillazine.org/Browser_will_not_start_up