There were large numbers of small companies that distributed the programs for free. The most famous was the McAfee group, with its DOS-based VirusScan program. As time went on, these programs were all bought by one company or another. The major competitor to this behemoth is Norton AntiVirus, which has been around just as long and has amassed a following that is just as large. This product has been around for years, and has gotten easier to use every year.
Updates are very important, because new viruses are created all the time.
These companies examine new viruses and find ways to clean them off your system. By updating your anti-virus program, you are ensuring that these new virus detection techniques are being used. It checks all files you use on the fly, and even checks your Internet connection to make sure any nasty Java or ActiveX applets don't start messing with your data. NAI McAfee VirusScan VirusScan has its roots in a more professional atmosphere. It has integrated the popular Dr. Solomon virus engine NAI bought up.