All I can think of to try is re-inserting known-good, fully charged batteries amd toggling the power until the body resuscitates. Was the battery fully charged BEFORE you started the cleaning process? Because the only time I've seen this happen is when someone lets the battery die while the body is holding the shutter open for cleaning.I was cleaning my sensor on my D810, when I finished I attached my lens and tried to press the shutter but my battery is dead.
I put in a freshly charged battery and no power. Does anyone know how to fix this problem?