If you get a email or phone call from someone stating that your computer is infected and you need to call some number, DON'T DO IT!!! They will ask for remote access to your computer to convince you to pay them for doing nothing. Worse, they may infect your computer so that you NEED to pay them.
NO legitimate company will call you to tell you your computer is infected. They may say they are from Microsoft but don't believe them! Best idea is to not contact them or hang up and block the number.