Hi Guys, I'm new here, and am writing cause I don't what to do anymore, here' my situation.

My wife got a Fox, like 2 months ago, I have to use the battery for another car, so I use the battery of the fox, well 3 days later I put it in again, what is my sorprise, the don't start the engine, the battery is fine, but the engine, don't want to start, so as normal person I search on the net, and nothing, I don't want to take the car to the dealers, it's to much expensive, so and writing here to see if anybody can help me with instructions.

The problem its apparently the key, the ecu and the alarm, they don't have a sync, everytime I try to start the engine the EPC light blinks and sound, I check every fuse and they are fine. A friend told me this Switch Ignition ON and leave the key in the ignition, pull out the tip on the battery for 15 min then put it on and wait another 5 min, then try to start the engine I did it but nothing happens the engine dont wanna start

So I came here if anybody knows this problem and wanna help me out it would really appreciate.

The fox it's 2006, 1.6

I'm writing from Caracas

Regards