Oh - one bit of clarification: When I right click, the box that I used to use to let me open a link in a new tab does appear, but it does nothing when I do so.

I appreciate your help.

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

You can try to disable hardware acceleration in Firefox.

• Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"

You need to close and restart Firefox after toggling this setting.

• https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration

Tried all that just now. No change.

Help!

I notice that you have the Open Link in New Tab extension, so I assumed that this extension isn't working properly.

Did you try to start Firefox in Safe Mode?

Can you open a link in a new tab with a middle-click or if you hold the Ctrl key and left-click?

You can re-enable hardware acceleration if disabling didn't help you with this issue.

Yes, I restarted in Safe Mode, and it still didn't work. Then I followed the instructions above, restarted, and it still doesn't work.

My mouse is a 2-button, but I did push the Ctrl key and left clicked and got a new tab.

Do other entries in the right-click context menu menu work like opening the link in a new window (Shift + left-click)?

Shift + left-click works.

Right clicking opens a tall box with a long list of options to click on. I tried opening in a new tab, a new window, and a new private window. None of them work.

Sounds that the right-click context menu is broken.

Try to create a new profile as a test to check if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Well, how would I know what files are corrupt, and, thus causing the problem?

You can one file that has data that you want to recover at the time and check if it is still OK or that the problem returns. That should allow to pinpoint the culprit and it might be possible to repair the old profile.

This is over my head. I don't know how to do that.

What data is important that you want to keep?

I assume at least the bookmarks and possibly passwords. You can copy the places.sqlite file and the files in the bookmarkbackups folder. For the passwords you can copy the logins.json and key3.db files.

You can also try to reset Firefox to create a new profile if copying files is too difficult.

• https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings

When you reset/refresh Firefox then a new profile is created and some personal data (bookmarks, history, cookies, passwords, form data) is automatically imported. The current profile folder will be moved to an "Old Firefox Data" folder on the desktop. Installed extensions and other customizations (toolbars, prefs) that you have made are lost and need to be redone.