Update your antivirus software
Antivirus software must be updated regularly to stay effective against new viruses. Most antivirus software is designed to update automatically, but you can also update your software manually.
Windows does not come with antivirus software, but can often detect and monitor antivirus software that you or your computer manufacturer installs. The status of your antivirus software is typically displayed in Windows Security Center.
Open Security Center by clicking the Start button , clicking Control Panel, clicking Security, and then clicking Security Center.
Click Malware protection.
If Windows can detect your antivirus software, it will be listed under Virus protection.
If your software needs to be updated, click Update now.
If your antivirus software is not displayed in Windows Security Center, go to the downloads section of your antivirus software provider’s website. Find the update for your version of the software and your operating system, and then install it. For more information, check the Help for your antivirus software.
Most antivirus software updates are free, but some providers charge a small fee for the updates. If you're using an older version of the software, you might also have to pay to upgrade to a more recent version to continue to receive the updates.