This page has links to free programs that you can use to protect your home computer from computer viruses, hackers, and spyware. If your computer currently is not protected from these common threats, you can go to these sites to download the software to install on your computer. Since most of the sites listed also have for sale versions of the software, you may have to hunt a little for the link to the free versions.
Free Antivirus Software
Internet Security Suites from your ISP
If you have internet access at home, your internet service provider may offer an internet security suite that will include at a minimum, antivirus and firewall software for free.