they only follow tasks given by the programmer, ive done robotics and computing, if u give robots sensors, it can only react to certain situations if uve allowed it to do so, if not it just halts the process, and waits for a human, tehy have no capacity to learn or evolve. this include virii, its true that klez evolved to include CIH, but thats only because the worm ran on an infected machine, and to CIH the worm was only another file to infect. its just luck that this happend.
a virus cannot choose its payload, it is told what to do and when to do it when the programmer chooses it to do so.

preep