It's a harmless memory resident boot virus. It hooks INT 13h and writes itself to MBRs of hard drives and boot sectors of floppy disks. It contains text strings:
THIS PROGRAM WAS WRITTEN IN INDIA.(c)1993 FAT AVENGER PS. this program is not meant to be destructive
Allow F-Secure Anti-Virus to disinfect the relevant files.
For more general information on disinfection, please see Removal Instructions.