I'll try to keep this short but at the same time provide as much information as possible, here it goes.
So I had an old pc and thought it was time for some new parts and ordered the following:
Motherboard: Gigabyte ga-z77x-d3h
Video Card: Asus HD 7970 Matrix
CPU: Intel i5 3570
RAM: G.Skill Ripjaws X F3-12800CL9D-8GBXL which is 2x4gb
SSD: Samsung 830 series 128GB | MZ-7PC128B/WW
For my old setup I used a NVIDIA Geforce GTS 250 and I still had a PSU which was a Cooler Master silent pro M600.
I also still had two old HDD's, which are both a Samsung HD753LJ and I'm currently using my old case, a Cooler Master HAF 932 Advanced. The monitor I'm using is a Philips 220CW8FB 22".
When my new components arrived I installed them externally, on the motherboard box it came in. Installation went without any problems, installed the CPU with Stock fan and after that installed the RAM, video card and some cables to power everything. However when I booted my pc the monitor would just keep on saying: no video signal, which is what it's always saying when I have my monitor turned on without the pc being turned on, even with my old setup. All the fans were spinning, both the fans on the video card as well as the fan on the CPU.
So I tried switching the video card from the top slot of the motherboard to the middle slot and I also tried out different combinations as in: video card top slot, DVI adapter in port A or B of the video card and switch this around to make sure it wasn't something silly like that. I also tried out the VGA slot on the motherboard but that didn't seem to work either with my new video card plugged in.
After not much thinking I then just installed my old video card, the GTS250 into my new motherboard and it worked. Both the onboard video card in the motherboard as well as the video card itself worked. Now after some searching on google I thought it might have been my PSU so I bought a new PSU, the XFX ProSeries 750W XXX edition. Installed it this morning and tried out if my video card was now working. Seems like I wasted some money there because it still wasn't working.
Now I'm thinking it might be a defect of the video card but I'd like to get some of your opinions before I return my video card and have to pay another 20-50 euro's as fee because there was nothing wrong with it.
There are 2 red and 2 green LEDs on the video card where the PCIE cables plug in which indicates whether or not the cable is working and they are both green, fans are spinning but that's about it. I've tried resetting the CMOS a couple of times but to no avail. Also tried the safe mode button on my video card which should do pretty much the same thing but that didn't work either.
Now when I have my new video card installed it seems like my pc just won't boot at all because neither my mouse or keyboard get powered.
So here is the big question, what the flying monkeys is wrong? Is it my video card, or is it my motherboard? Is there anything I could try before returning it?
Thanks in advance and if you need any more info, please ask and I'll try to answer you as best as I can. I know there's a lot of threads out there but every problem is different and the solution is mostly something that I've already tried.