Bring your Nuvi into the very "dark" room.
Turn it on and try to see the light appear or not.
I did system software missing with my 37xx and it did not boot.
I saw "the light" when I try to power on.
It means nuvi is powering on but won't boot normally. (because boot = fail)
drag .rgn on updater., --> Plug in USB.,--> power on --> press finger --> You will see the word ""system" if you have a good luck.
Nothing to lost., just try it.