98 crysler t&c problem to start

Sometimes it starts and works only for three sec and after shut down. After third attempt to start it doesn't start at all. During that time the dash board doesn't even blink-no speedometr, fuel tank, or transmission; only the top part is still working-parking, chek engine, , oil, airbag etc. Light ant stereo are working, so it seems like the main computer doesn't work. But, the strange thing is on the next day i can start and drive fithout any problem, and only after a week and maybe 6 months it can repeat again, it seems without any cause. In concluson, after all no codes.