This is a virus detection. Viruses are programs that self-replicate recursively, meaning that infected systems spread the virus to other systems, which then propagate the virus further. While many viruses contain a destructive payload, it's quite common for viruses to do nothing more than spread from one system to another.
Indication of Infection
The virus keeps track of the elapsed disk usage time since initial infection, and does no harm until it has reached a predetermined limit. The predetermined limit is approximately 48 hours. (On most systems, Disk Killer reaches its limit within 1 - 6 weeks of its initial hard disk infection.)
When the limit is reached or exceeded and the system is rebooted, a message is displayed identifying COMPUTER OGRE and a date of April 1st. It then says to leave it alone and proceeds to encrypt the disk by alternately XORing sectors with 0AAAAh and 05555h, effectively destroying the information on the disk. The only recourse after Disk Killer has activated and encrypted the entire disk is to reformat.
The message text that is displayed upon activation, and can be found in the viral code is:
"Disk Killer -- Version 1.00 by COMPUTER OGRE 04/01/89
Don't turn off the power or remove the diskette while Disk Killer is Processing!
Now you can turn off the power. I wish you Luck!"
It is important to note that when the message is displayed, if the system is turned off immediately it may be possible to salvage some files on the disk using various utility files as this virus first destroys the boot, FAT, and directory blocks.
Methods of Infection
The only way to infect a computer with an MBR/Boot Sector infector is to attempt to boot from an infected floppy diskette. The boot sector of the diskette has the code to determine if the diskette is bootable, and to display the "Non-system disk or disk error" message. It is this code that harbors the infection. By the time the non-system disk error message comes up, the infection has occurred.
Once the virus is executed, it will infect the hard drive's MBR and may become memory resident. With every subsequent boot, the virus will be loaded into memory and will attempt to infect floppy diskettes accessed by the machine.
Computer Ogre, Disk Ogre, Ogre