I have security pop from firfox about Trojan Deteced and Warning virus Deteced and McAfee out of Date

See Web Push notifications in Firefox — the article shows where to revoke the permissions you granted in past.

Long answer is these are not from Mozilla nor the desktop Firefox web browser. If these are as small popups on bottom right of Firefox window then these are just web push notifications from sites you have allowed to send you notifications. Unfortunately instead of useful information some may send you junk, spam, fake virus/trojan alerts etc.

Just revoke the sites as shown in KB article link in above reply.

Thanks James, I recently linked my phone to the laptop and downloaded WhatsApp to the laptop. I uninstalled WhatsApp did a history etc clear and the problem seems to have gone away. Alan