Quote Originally Posted by bkk2009 View Post
But I cannot access the device. It will not let me do a hard reset. It does not show up as a USB device in Windows. Updater says no usb device connected. Even the Garmin website cannot detect the device. What can I do?
It will not let me do a hard reset --> Hard reset won't help you.

But I cannot access the device.--> Yes., right ! so I said you have to access pre-boot mode for connection.

It does not show up as a USB device in Windows--> also right.

Pre-boot mode
1). when garmin logo appear., press your finger above "G" of "GARMIN"
2). you will see a little "system"
3). now you are in pre boot mode

0).on computer.,--> drag rgn file on updater.exe., -->select USB
1).Plug in usb with 3790
2).access pre boot mode
3).when you see "system" on 3790., plug in usb into computer
4).You will see your device detected on Updater.exe
5).Press OK on updater.exe
6).Still press your finger till complete updating firmware.

Good luck