Hi MsNbell, to prevent Firefox from recovering your previous session windows and tabs, you can hide your session history files from Firefox. This old reply has the steps for that: https://support.mozilla.org/questions/1188460#answer-1037431

Does it work for you?

By the way, there are a few common patterns to these annoying pages.

(1) Large alert dialog (lots of text)

If you cancel this dialog, it may reappear. After two or three appearances, Firefox should add a checkbox at the bottom of the dialog to stop the site from showing more alerts. Check that box and click OK to block further dialogs.

(2) Authentication dialog (asks for username and password)

If you cancel this dialog, the page may reload and immediately show it again. Pressing the Esc key numerous times in a row can cancel the reload as well as the dialog.

(3) Reacting to mouse movement

Some pages have a script that detects when you are moving the mouse pointer up toward the tab bar and takes action to show another dialog. On these pages, try using the keyboard shortcut Ctrl+w to close the tab instead of the mouse.

After, Go to the Mozilla Add-ons Web Page {web Link} (There’s a lot of good stuff here) and search for a good ad / pop-up blocker.

Thanks!! After running Malwarebytes then logging into Mozilla via Explorer I was able to get rid of the adware. I do have pop up blockers but must have been careless in allowing some access. grrrr!