When the virus is run, it infects all .COM files and attempts to infect the master boot records of hard disks and floppy disks. However, the virus does not check to see if the disk it is attempting to infect is write-protected. If the disk is write-protected, the system will show the user an error report. When the user looks at the directory of a .COM file, the file will increase in file size.
If the computer is booted on Thanksgiving of 1990 or later, the virus will overwrite the first seventeen sectors of the first two heads of the hard disk, which renders the partition table unusable and makes all data inaccessible. If the user reboots on this date or later, there will be no boot sector on the hard disk, which makes the system unable to boot up.