Most folk call this "flashing the phone." I won't detail how to do this but your cell phone counters do it a lot and Garmin should be able to service the phone. You should not have been able to wipe out the OS on the phone by formatting it from the PC. I have another model of the Garmin phone and it can't be wiped out like this.
It also has no viruses I know of.
i am using garmin asus nuvifone (model no.: M10), smart phone 3; it is a windows mobile, now the problem is that, 3 days earlier when i was taking backup of the internal memory by connecting it to my desktop pc via usb cable, i found out innumerable viruses & worms, even how i successfully took the backup, but after that i formatted the entire internal memory...it was my biggest mistake, my phone went off,,, due to formatting the entire operating system is deleted,,, so now it is not loaded, & thus my phone is now unable to boot... when i push on the power button, i am only able to see the "GARMIN ASUS" screen... that's all,,, now i m in a great confusion, what to do? i tried 'Hard Reset' but it didn't worked at all,,, i think that i need to reinstall the OS,,, but how,,, please help me??? my email id is firstname.lastname@example.org