Do I need Norton or Mcafee? They both say that I'm infected.

All such messages are scams presented by criminals. Close the offending page and then avoid sites that are involved in such bogus advertising.

Phony "tech support" / "ransomware" popup… - Apple Community

You shouldn't be running more than one anti-virus on a computer.

If you are getting emails purportedly from Norton or McAfee, those are scams.

Generally speaking you don't need anti-virus utilities on a Mac from third party. Apple has its own background program called XProtect. Additionally the root account is disabled by default, and all firewall ports are stealth by default. How you respond to an email or website that says you might be infected you can open the gateway to hackers.

Command-option-escape on Mac OS brings up the force quit utility if you don't have anything to save in the currently open application, and you can quit a program directly. Browsers can reload their base home page with the shift key held when you open them up from scratch.

Then you can clear caches in your browser preferences.

Malwarebytes is a good free manual diagnostic tools for malware.

To remove any program without an uninstaller, use AppDelete

If you are uncertain if a program could be running in the background, run Etrecheck and report its results.

Absolutely not ... it's a scam.

Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support