You are describing two different problems.

eddie55 said

If I already have firefox open, if I click on a hyperlink the link opens to a second tab on the same page as the already opened window.

Type about:preferences#general<enter> in the address bar. Under Tabs, turn off; Open new windows in a new tab instead

Hello. Does not solve. Still two different browsers open when I click hyperlink. I have used Firefox for years and this recently started after one of the upgrades

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options) key, and then starting Firefox. Is the problem still there? ++++++++++++++++++++++++++++++++++++++++++++++++++++ Minimize the browser to the task bar. Now give it a try.

Hello,

Great. I disabled AdBlock plus and back to normal. All of my other add ons work fine. Thank You for the help

Glad to help. Safe Surfing.