D700 troubles

Sep 6, 2020
Howdy I have some troubles with my Nikon D700. 1st some back ground, I have had it since new, 2015. I haven't had any troubles with it till now, I have taken 14419 shots with it, it’s never been dropped or submerged, only had 1 lens on it, Nikon 28-300mm. Okay yesterday I was going to take a small hike close to home along the river (Columbia), At home I dropped the battery in it from the charger, turned it on, The top panel came on, went to the back, clicked the menu button “nothing” checked the top again, it was still on.
So I went outside and took a few shots, went back in, hooked the card up to my computer and the images where there, nothing wrong with them.
Back inside and I have David Busch’s Nikon D700 manual, open that up and I couldn’t find anything in there, any ideas what the problem could be.

Thanks in advance for any help, but I’m pretty sure I know where it has to go.