Update

Managed to load some maps
and 1 time managed to use WEBUPDATER to load 4.30 firmware
but I must have messed up the file structuree so much by now (following the various tips I found on the web)

when I start the unit, the garmin logo appears, and then shuts down.
I cannot do a reset or get in the pre-boot screen

on USB power/cable, the logo appears but that is all

I can see the unit in EXPLORER and in the files structure (I took the SD card from the unit) I can move files around (the garmindevice.xml is goen though...) but where to start? Like I said, things must have been completely messed up.

Is the a way to "rebuild" the Nuvi 510 completely (since I can access the unit via explorer)??
Or rebuild is as a zumo 220, I do not care, as long as the unit will work! :-)