Skism

Virus.DOS.Leprosy.Skism.1992 or Skism is a virus that runs on MS-DOS.

Behaviour
Skism is a pretty destructive virus that will prevent boot on a certain date. When you launch the virus on the 25th of any month (if the day is Friday), it will display the message below. Rebooting on this date causes the message to show up again. It is impossible to get any work done on Friday the 25th.

Videos