Intel Motherboards - Ajuda Problema Boot z97x killer.

Hi everyone, my name is Wallace and I'm from rio de janeiro, I currently own a z97x killer equipped with i7 4790k 4.5 mhz with 1,230v, before i had a 4790 nonk i7 and it would be fine after the exchange for the 4790k, if the option in the bios called spread spectrum if it is activated the machine does not boot and when I put it to restart the pc it would be on the black screen without video, ok I disabled the spread spectrum, apparently it went well, until the other morning, time off, first it does not boot, then I disconnect and I connect it works, what can it be? I already switched bios to 2.50, I got back to 1.30, the problem persists.

after a long time off, the computer does not start the video on the first boot, I switch it off and on, it works normally all day. help me please. Cry