The 'FakeFormat' is a trojan program. Being run it overwrites boot sector and both FAT copies of diskette in drive A: assuming that there's a 1.44 mb diskette is there. After that a diskette boot sector contains a stub that will output:
This is a DATA disk only; Insery system disk, press any key when ready.
The trojan waits for keypress and if CTRL + C combination is pressed exits to system, otherwise it loops (starts ist code from the beginning).
Allow F-Secure Anti-Virus to disinfect the relevant files.
For more general information on disinfection, please see Removal Instructions.
Technical Details: Alexey Podrezov, F-Secure