This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

After clicking on Firefox the winodw never appears, but firefox shows up on the Task Manager using all the CPU. Have uinstalled and reinstalled latest version.

  • 5 replies
  • 3 have this problem
  • 3 views
  • Last reply by John99

more options

I start Firefox, but it never brings up a Window. "firefox" shows up in the task manager using all the CPU. I have uninstalled and reinstalled version 12, but it is still doing the same. I had it remove the profiles and I deleted the the folder from Program Files before reinstalling. When you boot to Safe Mode with Networking, Firefox does come up and works.

This is on a Windows XP SP3 system with 1GB RAM that is up-to-date on all security patches from Microsoft

I start Firefox, but it never brings up a Window. "firefox" shows up in the task manager using all the CPU. I have uninstalled and reinstalled version 12, but it is still doing the same. I had it remove the profiles and I deleted the the folder from Program Files before reinstalling. When you boot to Safe Mode with Networking, Firefox does come up and works. This is on a Windows XP SP3 system with 1GB RAM that is up-to-date on all security patches from Microsoft

All Replies (5)

more options

When you boot to Safe Mode with Networking, Firefox does come up and works.

That would seem to indicate some third party software is interfering with Firefox. Prime suspects are usually security related software. If that is not the case work through the list of things that startup in normal mode but not in Windows Safe mode.

What security related software is in use ?

Given that you also have high CPU usage and Firefox running you may need to consider the possibility of malware.

Modified by John99

more options

The system is running Norton Internet Security 2012. The system has been scanned by Norton, MalwareBytes Anti-Malware, and Spybot and tested clean. So I don't think malware is the issue, but I will scan it again.

more options
  1. Check and reset NIS 2012 settings, ensure it does not block Firefox.
    If that fails
  2. Then Physically go off-line pull the plug or WiFi connection. Now that it is safe as you are not connected to the Web try with NIS2012 installed.
more options

I uninstalled NIS2012 and firefox still gets caught in the CPU loop and will not open a window.

more options

You know Firefox works when Windows Safe-Mode is used, but not when you start up Windows normally.

Unless someone else comes up with a suggestion I think it is down to a hard slog process of elimination. Look at all the things listed as starting when windows opens, and look in task manager at all processes that are running when you try each method. One of the additional processes is likely to be the cause of the problem.