Summary

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).

[Analysis: Alexey Podrezov, F-Secure]