Is a personal anti virus a scam and if so how do i get rid of it?

A few hours ago a pop up appeared on my computer, it then scanned my computer and claims i have 41 viruses and that to get rid of them I need to pay 50 dollars. I then closed out of it and now its in my start menu and pops up every few minutes claiming all the viruses I have and how my computer will be ruined. Can someone please help me