Explain why a computer cannot solve a problem for which there is no solution outside the computer.

Either there is no solution, as in there has not been a way discovered (An algorithm) to figure it out. In that case, a computer can also not figure it out, as it requires humans to write algorithms to solve the specific problem. The second case is how you interpret it: There are some problems that are just not computable.

i prefer xbox one. : )

(because i need 20 chars)