@jknilinux,
Well, IMO, there's only one sign of consciousness, and that's knowing a semantically closed language and using it to communicate with oneself.
According to this definition, yes, computers can become conscious. There are none currently, though, because all they do so far is simulate the outward effects of consciousness (quite poorly, I might add) while not actually fulfilling the definition of consciousness.
If a computer did actually use a semantically closed language to refer to itself, then it would become conscious, though.