BadneckRedneck

I haven't overclocked anything on this system, so that's not it
The strange thing that I forgot to mention was that I didn't get any crash dumps or BSOD's, but I will borrow my friend's 600W PSU to check if the problem is my PSU

bad cable/ connector
 

Try removing your gpu and use your cpu as your gpu. If it starts booting try going into the bios and check the temps of your cpu. If your processor is overheating it could lead to crashes.

and 2 way sli is not the smatest decicion, if you need a good gpu, pick a rx 480 or a 1060 or 1070 depending on your budget what you have left

Get a 6600 so it can share the same numbers with your old one.

Changed to Berlin and it worked, Thanks
 

I would disagree. You can't predict the future, but the way that games and software's heading now, 4 physical cores would be better than 2 physical and 4 logical (in total)