My car was fine until today. it was running great, i parked it, and when i tried to restart it later nothing happened. i turned the key all the dash lights and radio and everything electrical worked fine but when i turned the i got nothing. no click or anything just dead. i tried removing and replacing the relays and nothing. then it started again. i thought it was all better. i got about 100 yards down the road and it went dead while i was driving, i tried to restart and got nothing again. i did the same with the relays, (not knowing if it helped or not) waited a couple of minutes then it started again. what could be doing this? i'm nervous about going anywhere.