I have a question. My Nikon D4 isn't coming on after I just used it yesterday. Could it be the battery? It not even coming up when I attach it to my computer either. Any ideas of what the issue may be?
Double check battery is fully charged.
Is the power switch loose? Does it click into place? Mine was all loose at one stage, it still turned on and off but there wasn't that click into place. I had them replace the switch when it went in for a service.
Could be the battery latch not turned all the way in when you insert the battery door, or maybe the latch is not clicking on the switch inside, worth a look.