Astra 1.8 fault

I have an Astra 1.8 works well one day up to 7 days and suddenly I am running when the motor witness is turned off and the one with the English key has, the sliding witness also illuminates. To turn it on again, a battery terminal must be disconnected and it works and works well for weeks.
They have already reviewed it and the concessionaire and they find no problem but change pieces, if someone has how to solve it I appreciate their help.

Greetings

Hello everyone, Lezapatalopez, reading the forum, I found your case. I can tell you that I have seen Paecido problems, in Varies GM cars. As a recommendation when you fail, do nothing, and try to scan it, so as not to erase fault codes stored in the control units that are generated and be able to diagnose. In any case, I can tell you that in the similar cases that I have seen, they stop, they are dead, the chek motor *English key in GM illuminates and the witnesses of traction control are lit and & or stake, they are usually generated due to communication problems between electronic modules *Net Diagnosis to the electronic system.