Did you try to boot the computer in Windows Safe Mode with network support?

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

Yes and crash reporter comes up immediately when i go to start firefox

Do a malware check with several malware scanning programs on the Windows computer.

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware

Please scan with all programs because each program detects different malware. All these programs have free versions.

Make sure you update each program to get the latest version of their databases before doing a scan.

• Malwarebytes' Anti-Malware:
  http://www.malwarebytes.org/mbam.php
• AdwCleaner:
  http://www.bleepingcomputer.com/download/adwcleaner/
  http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  http://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender:
  http://windows.microsoft.com/en-us/windows/using-defender
• Spybot Search & Destroy:
  http://www.safer-networking.org/en/index.html
• Kasperky Free Security Scan:
  http://www.kaspersky.com/security-scan

You can also do a check for a rootkit infection with TDSSKiller.

• Anti-rootkit utility TDSSKiller:
  http://support.kaspersky.com/5350?el=88446

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked

And after,

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

Jsr7711 said

FredMcD said

See if this works; https://ftp.mozilla.org/pub/firefox/releases/45.9.0esr/

i could not find a setup file in the earlier version zip file.

Rather than use a ZIP file, look in the relevant language/locale folder for the EXE installer. For example, for 32-bit Windows, US English:

https://ftp.mozilla.org/pub/firefox/releases/45.9.0esr/win32/en-US/

If you prefer a different language/locale, click up a level (the .. link) and look for your language code. If in doubt, check your URL while you're using the support site, and it should be in there just after support.mozilla.org.

That was helpful to have the .exe but still same problem with that version.

It took me awhile to figure out the sfc. for anyone following this thread, i got it to work by going to the start box and typing cmd to get the windows box. Then I typed sfc/scannow without the .exe (that was hard to figure out for me) After running the sfc nothing was found

And i ran adware cleaner, malware bytes but still have to check out the others.

I went down the entire list provided by Fred for adware, I ran everyone that would run on an XP machine.

I ran sfc again with nothing found wrong.

This is such a baffling thing. I still get the crash reporter when attempting to start firefox

I think you should also post your question here; https://support.microsoft.com http://answers.microsoft.com/en-US/windows/forum/windows_10

I was looking at the crash report which I posted earlier and I see something interesting. One line says "BlockedDllist". Could this mean somehow within windows a DLL was blocked? I have looked at the anti-virus programs and there is nothing spefically blocking firefox, but could there be something buried with Windows that possible Microsoft Security Essentials would have blocked. I have heard of Blocked Dll's but i have no way of knowing where to find where that is done or how it can be unblocked. Any ideas? Continued Thanks

Note that you should leave a space between sfc.exe and the /scannow command line switch.

After the cmd.exe prompt, type: sfc.exe /scannow and press Enter

• https://en.wikipedia.org/wiki/System_File_Checker

Hi cor-el, interestingly at the dos prompt i just type sfc/scannow and it begins to work and I see the scan window. No exe or no spaces. Leaving the space merely lists out the switches available with sfc but takes no action. sfc/scannow actually begins the scan. I have replicated this several times. it will also work with sfc.exe/scannow .

Though the scan consistently shows no errors, the dos window will not close without a forced close.

The DOS command window will not close until you type Exit.

I created a Dos batch program to run SFC for me. Its name is; sfc scannow - Shortcut ===Run As Administrator===.bat

C:\Windows\System32\sfc.exe /scannow Pause exit

Pause keeps the Dos window from closing until you want it to.