PONTIAC ELECTRICAL SHUT DOWN

Hi, I Hope Someone Can Help. I Parked My Car For, And Left For About An Hour, Came Back And Had No Power To Anything, No Door, Ping No...

I Have The Car Listed Above Fr 3.4l With 160,500 Miles On The Body. I’ve Replaced The Motor Like Complete Replaced Crank Rods Pistons...

Car Started With No Problem. Turned Car Off To Go Get Something. Came Back To Restart Car, No Power To Anything. No Lights, No Bells...

Was Driving Last Night Went Over A Set Of Rough Tracks And Lost All My Lights. I Have Reverse Lights And Warning Lights Like Door Ajar...