No one can tell from a distance whether your computer has a virus! Any phone call telling you that you have a virus, is a total scam. They will certainly want you to send them money to fix it. They might even tell you they need remote access to your computer, and will walk you through the steps to give them access. Once they’re in, they’ll look for your bank account and other stuff they can steal. Or worse yet, they’ll use your computer to store their own illegal files. JUST SAY NO!
Older folks are particularly vulnerable to these scams because they believe the caller when they say they’re from Microsoft, Dell, or some other reputable company. Educate your parents, your friends, and everyone you know.