Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Hi cor-el - I restarted Firefox in Safe Mode and then tried the trigger website that I mentioned above. Not much changed. The website partially loaded and then locked up (normal behavior with this problem). I was unable to open any other programs on my computer while Firefox was locked up. The only difference that I saw in Safe Mode was that I was able to use my mouse to move the cursor around the screen. Otherwise, I was still dead in the water for well over a minute.

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) as a test.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/

Do a malware check with several malware scanning programs on the Windows computer. Please scan with all programs because each program detects different malware. All these programs have free versions.

Make sure that 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
• https://support.mozilla.org/kb/troubleshoot-firefox-issues-caused-malware

Some added toolbar and anti-virus add-ons are known to cause Firefox issues. Disable All of them.

Could I suggest this test: set the Flash player to "click to play" so that sites require your permission to use it. Firefox should load the rest of the page more quickly and you can decide whether the site needs to be able to use Flash. (Sometimes it's just for analytics, super-cookies, or to play ads.)

Here's how:

Open the Add-ons page using either:

• Ctrl+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Plugins.

On the right side, look for "Shockwave Flash" and change "Always Activate" to "Ask to Activate".

When you visit a site that wants to use the Flash, you should see a notification icon in the address bar (looks like a small lego block) and one of the following: a link in a black rectangle in the page or an infobar sliding down between the toolbar area and the page.

Do pages load any faster?

You know, I just remembered something else that can cause a long lockup that occurs only once during a session and doesn't repeat until the next time you start Firefox. I'm not sure whether this is still an issue in Firefox 34, but it's easy to test. The issue occurred on systems with an unusually large number of fonts. This thread has more information:

• Firefox causes desktop to freeze. (Firefox 26)
• Firefox hangs on Websites (example: g2play.net) (Firefox 20)

The problem with disabling font downloading is that unfortunately many sites have switched to using downloadable fonts in place of small image icons, so then you get unintelligible little boxes instead of pictures... but please check it anyway.

jscher2000 said

Could I suggest this test: set the Flash player to "click to play" so that sites require your permission to use it.

Flash block {web link} Never be annoyed by a Flash animation again! Blocks Flash so it won't get in your way, but if you want to see it, just click on it

First, thanks to everyone for your responses! FredMcD and jscher2000- Today I tried setting Flash player to "click to play". The problem still happened. I had previously tried opening FireFox in Safe Mode which disables all Add-ons and that didn't work either.

jscher2000 - Your suggestion regarding the fonts sounds promising. I'm going to try that one in the morning and I'll let you know if it's successful at stopping the problem. If that does not work then my next step will be trying the various spyware/malware searches.

None of these options work and the thing still locks up randomly on different sites. I can't think of anything else to try except to install an older version. This started with version 35. I don't want chrome Google already gets too much info about me.

Hi Budieus, it looks like you started a new question, which is great, so let's continue there: https://support.mozilla.org/questions/1050095

Install an older version of Firefox {web link}