will not load maps or turn on after doing update

If you have not try to restart your device if that doesn't work restore the device if that doesn't work consult the company you bought the device from if they can't trouble shoot your problem then consult somebody from Garmin Nuvi.

Just have a horizontal line

I have a more mature Garmin Nuvi 755 and on my last update was instructed to install an SD card, which I did!I performed the update, and tried to use it could not enter location addresses and the road vs directions was not working right! I kept fiddling, reading , doing research and discovered that the recommendations of Garmin, that SD cards be formatted in FAT32 on a Google search! Took out the SD card and checked it and it was formatted in Exfat! Anyway formatted the SD card in FAT32 format and started all over again and instead of updating, there is a way on Garmin Express to reload all maps! It took about an hour but when done, all updates were installed and my mature Garmin Nuvi 755 will continue to guide me! It works perfect now! Ya would think when Garmin instructions tell ya to install a SD card, the instruction would include Format information also! Oh well!