Ford Repair: Ford Ranger just quit, ford ranger, instrument cluster

Question
My son has a 2006 Ford Ranger and he was coming home from work one day and it just quit. I mean it shut off like you had cut its power. The only thing that works are the lights. It does not even turn over. There is nothing. The battery is fine. Please help so that he does not have to experiment. They are telling him there is no way to check and see if the computer has went bad. He has been out of work for over a year and just now found a job and it is hard to be able to afford parts that are not needed. Thank you.

Answer
-k-, so i'm gonna assume you charged the battery, turned the key and nothing happens ?? doesn't crank over ? if it does after charging the battery you have a charging problem. does the instrument cluster light up when the key is turned on ? if it does then you can still access the computer info.