How does Computer virus work?

To make your system safe and clean you must know the very
basics of Viruses, Worms and Trojans. We are giving here what and how do they work
in short:


�Viruses� what
we used for computer are software programs are specially designed to interact
with computer operations, deleting data, spread themselves to other computers
by attaching themselves to a computer or a file over LAN (Local Area