no display after ram upgrade

Hi, I recently tried to build a new PC. I'm using a bunch of parts from my last pc, which was a b250m pro 4 asrock motherboard, a GTX 1050ti graphics card, 2x4gb 2133mhz g.skill ram sticks and an i5 7500 cpu. upon completion of it, i tried to start it up. it kept turning on and off. i fiddled...

So I bought new ram and put them in and they were different speeds than the old ones and now Im starting up with the old ones and there's no display. I've checked the placement of ram stick, I took out the GPU and put it back in, the monitor still says ' no input signal' but each time that I...

Mobo: MSI 970 gaming Cpu: fx 8320 Ram: 2x4gb corsair 1600MHz 2x4gb g.skill 2400 MHz Gpu : msi gtx 970 oc Psu: cooler master 500w 3 case cooler

Hi everyone, i bought i new sumsang 2gb ram 800mghz for my pc and when plug it in my pc turn on but there s no display on the screen. My pc is an HP pro 3130M with 2 sticks of 2 gb same as the one i bought. Please i need help as fast as you can