Choose a reputable antivirus software package which is updated regularly. Make sure that the upgrades are installed promptly. Many products distribute updates for download through the Web, and some products may provide e-mail notification when their products are updated. Release of monthly or bimonthly updates are usual, with emergency patches for new and severe outbreaks of viruses. Make sure that the scanner is run often.
Most products allow for automatic scans at prescribed times.
Make scanning a part of the maintenance routine. Back up the system regularly. Make backups of all application disks when they are received, on a system which you are assured is checked regularly for viruses. Hold the disk with the label or writing on top, and the holes pointing away from you. The latch will be on the right side.