Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

https://support.mozilla.org/kb/Firefox+is+already+running+but+is+not+responding

https://support.mozilla.org/en-US/kb/firefox-slow-how-make-it-faster

https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix

https://support.mozilla.org/en-US/kb/firefox-uses-too-much-memory-ram

https://support.mozilla.org/en-US/kb/firefox-hangs-or-not-responding

Tried all of that, as I said. I have also disable all add-ons since they stopped working.

Your System Details shows; Windows XP, Firefox 52.0

Are you using ESR?

You said all of your add-ons stopped working? Or was that in Safe Mode?

Yes, ESR.

Add-ons stopped running a few days ago, CPU usage issue has been going on for weeks and is worse.

Let’s do a full clean re-install;

Firefox ESR 52 version

Firefox; Extended Support Release {web link} ESR Notes System Requirements

<strike>https://ftp.mozilla. org/pub/firefox/releases/45.9.0esr/</strike> (outdated version)

https://ftp.mozilla.org/pub/firefox/releases/52.5.0esr/ current

Save the file. Then Close Firefox.

Using your file browser, open the Programs Folder on your computer.

Windows: C:\Program Files C:\Program Files (x86)

Mac: Open the "Applications" folder. https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac

Linux: Check your user manual. If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it. See Install Firefox on Linux; https://support.mozilla.org/en-US/kb/install-firefox-linux

If you downloaded and installed the binary package from the Firefox download page, simply remove the folder Firefox in your home directory. http://www.mozilla.org/firefox#desktop ++++++++++++++++++++++++++++ Do Not remove the profiles folder.

Look for, and rename any Mozilla or Firefox program folders by adding .old to them. Do not rename the Mozilla Thunderbird folder if there is one.

After rebooting the computer, run a registry scanner if you have one. Then run the installer. If all goes well, remove the OLD folders when you are done. +++++++++++++++++++++++++++ If there is a problem, start your Computer in safe mode and try again.

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode This shows how to Start all Computers in Safe Mode; Free Online Encyclopedia

Did that twice before I posted my question. Did it again earlier today. No changes.

Start your Computer in safe mode with network support. Then start Firefox. Try Safe websites. Is the problem still there?

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

Tried that earlier. Still the same, even starting computer in safe mode. Firefox still uses 100% of my CPU and slows down loading websites, with CPU usage maxed after it appears pages are fully loaded.

I called for more help.

For the time being, I'm no longer going to use Firefox. The problem is getting worse. As long as the browser is open, no matter what page I'm on, including this one, it is using 100% of my CPU, making it difficult to type things like this or do anything else, never mind the fact that no add-ons are working. The problem clears as soon as I close FF.

Please uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Then run Windows Disk Cleanup. Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. Reinstall 52.4.1 https://www.mozilla.org/en-US/firefox/organizations/all/

https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems?redirectlocale=en-US&redirectslug=Troubleshooting+extensions+and+themes

https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware and https://forums.malwarebytes.com/topic/9573-im-infected-what-do-i-do-now/

Sorry to see you go, we really think its all those add ons that you have in your profile. Windows XP is not supported for Firefox Release, but is for 52 ESR - keep using that and remove any un-used extensions for better performance. Please post back with what troubleshooting steps you did take and we can offer more support.

All the best, Rachel

I have tried everything suggested here and it has made no difference at all. There was even an update to Firefox ESR and it didn't help. Changing settings didn't help. Removing disabled add-ons didn't help. Disabling approved add-ons does nothing.

What I forgot to mention is that for more versions of Firefox than I can remember, pluginmanager.exe constantly crashes.

Also, Crash Reporter has not been able to send a report to Mozilla when Firefox crashes for years.

It is my opinion that all of these issues are tied together.

Even ESR 52.6.0 has the problem. Tabs look fully loaded, then the icon in the tab starts swirling (not the one in the bar), and CPU usage shoots up. Open a second tab and it and the private bytes shoots up even more. Close the second tab and the private bytes do not go down.

This usage even happens if a blank tab is the only one open.

It seems that as soon as wmiprvse.exe kicks in, the problems start.

Running anti-viral and anti-malware software doesn't change anything. Tried everything connected to problems with wmiprvse.exe. No help at all.

wmiprvse.exe = Windows® Management Instrumentation (WMI) is a component of the Microsoft® Windows® operating system that provides management information and control in an enterprise environment

Note: The wmiprvse.exe file is located in the folder C:\WINDOWS\System32\Wbem. In other cases, wmiprvse.exe is a virus, spyware, trojan or worm!

DrStrange10150 said

Running anti-viral and anti-malware software doesn't change anything

How many scanners did you try?

Further information can be found in this article; https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

Perform a System File Check to fix corrupted system files

Win 7, 8, 10, Vista: https://support.microsoft.com/en-us/kb/929833 Win XP: https://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/system_file_checker.mspx?mfr=true

Wiki - Windows 10 System File Check http://answers.microsoft.com/en-us/windows/wiki/windows_10-update/system-file-check-sfc-scan-and-repair-system-files/bc609315-da1f-4775-812c-695b60477a93

This link was changed;

Win XP: https://answers.microsoft.com/en-us/windows/forum/all/windows-xp-scan-and-fix-disk-errors/6fe2827a-4be6-4bc1-8083-5139b5aa3a3d

System file check run more than once. Did not help.

AdAware is always running with a full scan done once a week. Two anti-malware programs - Malwarebytes and SuperAntiSpyware, full scan run every other week.

A friend who also still has a computer running XP but doesn't use it that often is also seeing the same issues and has no more luck than I have in figuring this out.

I called for more help.

DrStrange10150 said

AdAware is always running with a full scan done once a week. Two anti-malware programs - Malwarebytes and SuperAntiSpyware, full scan run every other week.

I have had problems similar to that with WinXP, which I replaced with Win7 two years ago with a new PC, when SuperAntiSpyware was running all the time, which is the default installation mode of that application. Disabled that mode and the problem vanished. Can't say about Malwarebytes, as I never allowed it to run all the time; disabled that mode as soon as I installed it. Never used AdAware, so I have no idea about it.

And what about all those Plugins that are listed in your "More System Details" to the right of your initial posting? Have you removed any of those applications to get rid of their Firefox Plugins?

I you aren't using them, why not get rid of them, and eliminate them as a potential contributing cause. Sure got a *hitload of them installed.

    ActiveTouch General Plugin Container Version 105
    Citrix Online App Detector Plugin
    Coupons, Inc. Coupon Printer 5.0.2.3
    DivX Plus Web Player version 2.2.2.14
    DivX VOD Helper Plug-in
    Google Update
    NPRuntime Script Plug-in Library for Java(TM) Deploy
    Next Generation Java Plug-in 10.71.2 for Mozilla browsers
    Office Live Update v1.5
    DRM Store Netscape Plugin
    DRM Netscape Network Object
    The QuickTime Plugin allows you to view a wide variety of multimedia content in Web pages. For more information, visit the QuickTime Web site.
    RevTrax PrintMyCoupon
    Shockwave Flash 27.0 r0
    5.1.30514.0
    VLC media player Web Plugin
    NPWLPG
    Npdsplay dll
    Windows Presentation Foundation (WPF) plug-in for Mozilla browsers
    iTunes Detector Plug-in 

Firefox 52 ESR is the last version of Firefox which supports those Plugins; Adobe Flash being the sole exception in Firefox 52 Release and later versions.