1998 Cadillac Deville Electrical/won't start

Electrical problem
1998 Cadillac Deville V8 Wheel Drive Type unknown Automatic 125000 miles

Car started fine, driving on hwy, all systems working fine. All at once the blower for heat, radio, dash lights, windows stopped to function. Other electrical were still working. When I turned the car off it will not start back up. Where do I start?


update: we have pushed into garage and the radio will come and light for auto window buttons (about 1 in 3 turns of the key) head lights work, no dash lights except for what gear we are in. Does absolutlely nothing when we try to start. Will not start with a jump.