The motherboard and processor are fine. The question is the power supply. The GTX 750Ti. The base 750Ti has a power recommendation of at least 300 watts. What is the model number of your power supply?
That tells me nothing. There should be a label on the side of the unit. Take a picture of that and post it on a 3rd party image hosting site like imgur.com or tinypic.com.
Post a link to that image here.