How to undo the modification that starts moped without the key?

My boyfriend bought a moped from someone cheap, but it is hot wired to start without a key. Apparently it was stolen from the original owner, and when he got it back from the cops, it had been messed with by the thief. He tried to get it fixed (control panel, I think), but could not afford it, so he sold it to my bf. But we want to fix it because it is just asking to be stolen! We can only afford to pay a family acquaintance handyman, but would rather fix/repair it ourselves if it's not super difficult.

so anyone know how to do it, what it is, cost, etc?