V-Sign is a typical boot sector virus, except that it uses slightly
polymorphic encryption.
V-Sign infects DOS boot sectors on diskettes and Master Boot Records
on hard disks. It is only able to infect a hard disk when you boot
a machine with an infected diskette in drive A:. At this time the
virus infects the Master Boot Record, and after that it will go
resident to high DOS memory during every boot-up from the hard disk.
Once V-Sign gets resident to memory, it will infect practicly all
non-writeprotected diskettes used in the machine.
V-Sign doesn't preserve the original boot sector when it infects
a disk. The virus activates after infecting 64 diskettes. At this
time it will display a large V-shaped letter and hang the machine.