Another virus that came out at about that time, was Starship. Checksumming programs aim to detect a virus by the fact that it has to change executable code in order to replicate. Starship only infects files as they are copied from the hard disk to the floppy. So files on the hard disk never change. But the copy on the floppy disk is infected, and if you then copy that onto a new hard disk, and tell the checksummer on the new machine about this new file, the checksummer will happily accept it, and never report any changes.
Starship also installs itself on the hard disk, but without changing executable code.
It changes the partition data, making a new partition as the boot partition. No code is changed, but the new partition contains the virus code, and this is run before it passes control on to the original boot partition. Probably the greatest event of 1992 was the great Michelangelo scare. One of the American anti-virus vendors forecast that five million computers would go down on March the 6th, and many other US vendors climbed on to the bandwagon. PC users went into a purchasing frenzy, as the media whipped up the hype.