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
One indication of the Form virus is a clicking noise produced when any key on the keyboard is pressed on the 18th day of any month. Please note that if a keyboard driver is used, the clicking noise is undetectable.
Another symptom of infection is that your system will hang on a failed disk read.
Form consumes 2k of memory. The DOS MEM command will report 2k less memory. On a floppy diskette, CHKDSK reports 1,024 bytes of bad sectors. In the binary code of the virus, there is a message which identifies the virus, states that it does not destroy data and an expletive to Corrine. The message follows:
"The FORM-Virus sends greetings to everyone who's reading this text. FORM doesn't destroy data! Don't panic! (Expletive) go to Corinne."
This message is not displayed, but can be found using a disk editor.
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.
Form Boot, FORM-18