New files arriving on HAL-PC's BBS are automatically checked by the BBS software for viruses. From time to time he takes preventive measures to be sure nothing gets by. He's seen software attacks on his clients' systems. They aren't pretty. Such attacks are costly to the client's ability to get useful work from the system.
Prevention is the key.
Prepare for disaster. Don't wait until after it strikes. Create an emergency boot floppy disk right now. Grab a spare floppy and put it into your disk drive right now. Pick up one of the dozen America On-line floppies you received in the mail.