hi, that "urgent update" was not genuine but a scam tactic that is trying to trick you into installing malware! only download firefox from its official location at mozilla.org - in addition updates are handled automatically by firefox so you don't have to download anything (you can initiate a check for updates in the firefox menu ≡ > help ? > about firefox).

you should run a full scan of your system with the security software already in place and multiple other tools like the free version of malwarebytes, eset online one-time scanner & adwcleaner in order to try to contain the damage.

Troubleshoot Firefox issues caused by malware

There also is a Symantec cleaning tool for one of the infections going around which seems particularly resistant to removal. I'm not sure how to tell whether you need this, but here's a link for reference if the regular cleaners do not help.

Trojan.Kotver Removal Tool | Symantec

Thanks you to all responses that indicated it was not a real update. I have Norton Security, so used one of their heavy duty tools called Power Eraser and that seems to have solved my problems.

Thanks you to all responses that indicated it was not a real update. I have Norton Security, so used one of their heavy duty tools called Power Eraser and that seems to have solved my problems.