Okay, so if you get a black screen, no error, nothing, that means it isn't HDD, or Windows, or any software. It can be either the CPU, which should be okay then, the RAM, graphics cards, motherboard or PSU. I don't know that graphics card, but check whether you need a 4 or 6 pin PCI plug to power that card. The connector is either on th back end, or on the top of the heatsink usually. Check if you pluged in the 24 pin ATX connector into the motherboard, AND the 8 pin CPU connector, which should be next to the socket. Check if the RAM is seated properly, it clicked into the slot on both sides. If you checked all cables, but it still isn't working, you might need some professional help, or a friend, to test each of the culprits with a replacement.