Computer booting issue

i built a new computer a while back with some cheap parts. it always had a problem if u turned it off, the cmos had to be reset and everything wuz fine. now ive changed the mobo, and after clearing cmos and resetting everything up, when i tell it to save changes and restart, the display goes blank and never fully restarts. i know it s a power issue, but i cant figure out what it is... hwlp
!!!!