The most charming definition of intelligence i have ever heard is:
"'Intelligence' is what you do next when you don't know what to do next."
Using this definition, for a computer to show intelligence, it would have to confront a problem not covered by its programming and reprogram itself (re-invent its program) to solve that problem. Don't know if a computer able to do that has ever been built or even conceived. I think it would have to somehow include a random process generator, but that's just a guess.
Edited by AnswersInGenitals, : No reason given.