Yes, "The computer can't decide for me" is correct. You can also say it differently like this: The computer can't come up with a decision for me. The computer can't figure out a solution for me. The computer is unable to decide for me. The computer can't help me decide. The computer can't find the answer for me. You can also re-arrange the words I used in the sentences above to come up with even more ways of saying this. I hope this helps!

When our computer can not do something, we say "There is no app for that." It is a comical answer that means: Someone will likely soon make an application that does that. My computer is only a tool that enables me to make more informed decisions. If I drop my computer and it works, the answer will be yes. If it brakes, the answer will be maybe. After thinking about it a minute I realized there must be help for you Dimond. I was correct: There is an app for that. http://www.indra.com/cgi-bin/spikes-8-ball

Computers can't replace derision making.

or "This computer can't take decisions for me"

Yes, you can say "the computer can't decide for me." It would be the more usual way to express something like that, for example, in informal speech.