Hmm, the built-in search plugin uses https://www.google.com/ (at least for the US). I'm not sure why https://encrypted.google.com/ would appear if you were not intentionally searching on that site.

If you try https://encrypted.google.com/ directly, does it cause any problems?

When a page gets stuck, could you try clicking the x in the address bar to stop it and then reloading using Ctrl+Shift+r to bypass any cached files? Sometimes a full, fresh retrieval clears up a problem like this.

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

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

Turning off the extensions helped. Pages (Macy's and J C Penney were the worst offenders) loaded with no problem. I have no malware. I also only have three extensions activated: Skype Click to Talk (which I have disabled); the Firefox Classic Theme Restorer, and Blur, the new anti-tracking software from Abine. Now I have to see which one is causing the problem.

Thanks for the help. I'm grateful not to have to use Internet Explorer!  :-)

That is likely a content blocking extension like Blur, so check its settings.

cor-el said

That is likely a content blocking extension like Blur, so check its settings.

I just updated Blur and the problem went away.