need some help with my 68 valiant

I can not start at all. The car ran great it has a 360 in it and no trouble at all untill today.no lights,no radio,nothing at all.There is power to everything so i changed the ignition sleve but no go i need help

You can try the ignition switch on the steering column under the dash. There should be two bolts that hold it in place and of course the electrical connection. it takes obout five minutes to replace. I have changed them before and everything seemed to work once I did that. Good luck