Update Your Operating System with the Latest Patches
If the tires on your car were recalled because of a defect, you might still be able to drive on them, but you probably wouldn't feel safe. The same is true of your computer's operating system. Hackers rely on the fact that many computer users fail to install software patches on their machines, so they create worms and other malware to take advantage of these vulnerabilities. That’s why it’s important that you keep your operating system and security patches up-to-date. Simply running an anti-virus program is not enough.
It's easy to configure your computer to automatically seek out security updates, so that you don't have to remember to do it manually. Then, when you get that little message that says "new updates ready to install," all you have to do is install them.