Also noticed that simply typing in yahoo.com or any site results in same problem as above. Home pages open and function normally but any new pages spawned from a new tab never open. Have to open from a search engine.

That is inconvenient. I think this problem might be caused by the MEGA extension (unless they have updated it recently to solve this problem). You can view, disable, and often remove extensions on the Add-ons page. Either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions. Then cast a critical eye over the list on the right side. Any extensions that Firefox installs on its own are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. If you have MEGA, try disabling it -- along with anything else nonessential.

Sometimes a link will appear above a disabled extension to restart Firefox before the change takes effect. You can complete your work on the tab and click one of the links as the last step.

Any improvement?

Fixed thanks for the help.

Note that we have seen tab related issues as caused by a Mega extension,