Your MB does not support Pci-e 3.0 but that does not stop the video card from working in your computer. that video card is backwards compatable and will work in a pci-e 2.0 slot. Did you put the video card in the slot closest to the cpu socket?
The 700w psu is enough for the card that you have, is this a whole new build or did you have a video card in there and you are upgrading it? If you take the card out and turn the computer on do you get any beep codes. With the video card out can you use the intergrated graphics?
PCIe 3.0 support doesn't matter. It doesn't have it, but that's irrelevant because all PCIe 3.0 graphics cards work in PCIe 2.x and 1.x systems (PCIe is backwards compatible with the best version supported by all devices in the system).
Your problem is not PCIe version.
What are the rest of your hardware/operating system/relevant driver specifications, are you sure that you have all cables plugged in properly, and how old is your PSU?
I don't have AMD and have not used it either so with you getting the apu which is designed to give better intergrated graphics is there an option or setting in the bios that you have to change to get the Pci-e and the video card to work?
I think with Intel when you put a video card in the pci-e slot it automaticly switches from intergrated to video card.If you have the owners manual for the motherboard you can look in it to see if there is a setting that you have to change.