Computers cannot, and will not, ever be alive. Why? They feel no emotion. They are programmed to do things we tell them and they don't care about doing them. You could program a computer to kill a puppy and it would not care. No computer would care. However if you ask a human to kill a puppy some would cry some would be glad (those weird people). Thats how we are human. We may be programmed to react to the world around us however we react differently. All robots don't react at all to anything.

They do not feel emotions.

Love, hate, jealousy, sadness, pitty, bravery, courage, trust, integrity, humor, affection, companionship, lust, adoration. A computer can do none of these. A robot is a computer and computers do one thing. They compute. And computing requires no emotions.