Looking for advice about a problem i am having after a few upgrades.

Hello, awhile back i got the thought of upgrading my computer to a better graphics card and cpu i decided i was going to upgrade to a nvidia gtx 750 ti and a i7 4790k processor. Now in my computer i had the stuff that had already came with the computer the only thing that i had added in the computer was a graphics card (nvidia gtx 660). After setting my mind to get to these specs i then started looking at better cooling and at a better power-supply i decided on a phantek (http://www.amazon.com/Phanteks-Heat-pipes-Premium-Patented-PH-TC14PE_BK/dp/B007ZZE63A/ref=sr_1_16?s=pc&ie=UTF8&qid=1451664824&sr=1-16&keywords=cpu+cooling&refinements=p_89%3APhanteks) for the cpu cooling and for the power supply i decided on a evga (http://www.amazon.com/EVGA-Continuous-Warranty-Supply-100-W1-0430-KR/dp/B00H33SDR4/ref=sr_1_4?s=pc&ie=UTF8&qid=1451664925&sr=1-4&keywords=power+supply). After deciding i bought the power-supply the cooling and the graphics card, I'm planning on waiting to get the cpu at a later date when i get the money. After getting all the parts and installing them i ran into a slight problem the cooling fan was too big for my case i then started shopping for a case i settled on a phantek enthoo pro the case eventually came and i started moving everything over after i had moved over all the parts of my computer and plugged them in i went and plugged in the computer for the moment of truth and the computer didn't put out video all the fans were on but their was no video i also checked the mouse and keyboard no power there also, i immediately unplugged the computer rechecked all my work to make sure i didn't forget anything and i didn't all parts were plugged in after this i started looking online for advice from others i looked at what other people did to fix these problems they said to try a bios reset i did that still nothing. They also said to reseat your cpu i did that still nothing. They said to make sure the motherboard wasn't grounded i did that still nothing i went through these steps and eventually i got to the point where all i was seeing was people saying that it was the motherboard. Now I thought i would reach out and ask some people who are more knowledgeable about this than me before i go out and spend money on a motherboard, so is it my motherboard?