The Nuvi 780 kept continuously rebooting as a few files were corrupt. The service center here claimed the board is corrupt but i know it was my fault while carelessly copying files to the device.

I've installed the Garmin drivers, Web Updater and downloaded nuvi7xx_GCDfile__540.gcd in preparation.

Was able to use GarminCure3.exe to successfully load the Cure with nuvi7xx_GCDfile__540.gcd

The file system wasn't getting mounted in Windows so i used RMPREPUSB.exe with default settings listed in thread [Only registered and activated users can see links. ] to format the disk.

Now the Nuvi straight away gets into mass storage mode and i don't get any chance for Updater.exe to load back the original firmware. Am trying:

1. Nüvi is switched off.
2. Press and hold top left or right or both corners of the nüvi screen.
3. While still holding corner of screen, connected nüvi to PC via USB cable.

Have also tried holding power switch, then top left concern then connect to PC or hold power switch, top left corner, lock the power switch and then connect to USB.

Within a few secs it shows up as removable drive in Win 7 (32 & 64 bit). The Updater.exe application does not even momentarily display the device under USB for updating. Garmin Web Updater does not recognize the device even though it's listed as a drive letter.

What can be done to get the Nuvi 780 into pre-boot mode for updating to original firmware again using Updater.exe?

Thanks in advance for guidance on getting this resolved.