How does Antivirus work?

Antivirus has a unique feature which scans your computer against viruses, worms, and other malwares. You have to choose an antivirus that has an auto-protect that scans your machine in the background. It is necessary also to update it regularly or up-to-date. Antivirus alone will be useless if your windows firewall is turned OFF. You have to turn it on because it will add additional security for your computer. I suggest that if you scan your machine, you should be in diagnostic mode or safe mode for better chance of detecting the root or cause of trouble shooting. Antispyware is also necessary against antispyware or adware. That's it. Have a nice day.