Welcome to Nikonians! Sorry to hear of your problem. The r19 is normal when the shutter release button is pressed half way. From what you discribe, it sounds like there is a short in the shutter release button or wiring that is causing the shutter to release at start up. Does the r19 stay on when the camera is switched on?
When the shutter button is pressed half way, the LCD screen is disabled. If the shutter button is shorted so the shutter releases, this would prevent the LCD from turning on.
Do you have an MB-D200 mounted on the camera? Good Luck and Enjoy your Nikons!