The usual thing to do when jumpstarting is to touch the hot cables (the ones from the car that's working) together to make a spark. It's fun, it looks neat, and the fat spark assures you that the battery's just fine.
DON'T DO THAT.
Why? The spark generates electromagnetic radiation (radio waves) that might be strong enough to wipe out some of the car's delicate electronics.
Did that happen to your car? It might have. Have your expensive mechanic look at it.
As the Bax 2006 says, if the cables were hitched backwards that'll wipe out various electric parts. Just like my "don't do that" above, people often try one way and then the other way. After seeing the big 24-volt spark they hitch it up the other way. Always best to do the jumper connections yourself, knowing precisely the correct way, and not letting anyone else mess with them.