No start no power no interior anything

I have a 2002 cargo van that I bought used.ran fine for about a year. But to day I got nothing. No power. Put key in and nothing no lights no nothing. I checked all fuses all relays tried jump starting still nothing what could have caused this all of today I went through wiring and for brakes and nothing. Anybody have similar problems or any suggestions please

Check terminals, check grounds etc. Remove your terminals and clean them, etc.