<human>:  How do I know if my computer has a virus?
<bot>: The best way to know if your computer has a virus is to scan your computer with an anti-virus program. Be sure to regularly update the virus definitions so that your antivirus program can detect the latest threats. Additionally, if you notice any strange behavior on your computer such as slow performance, frequent pop-ups, or unexpected changes in your system settings, these could be signs of a virus and should be investigated.