So a few things. What mobo do you have? Do you see any debug code/led? Is the gpu securely inserted, and the little clip on the side clamped in? Did you hook the gpu up to the psu, with the right connector?
My cpu is a amd fx 6300, psu is a seasonic 450w 80 plus, motherboard is a gigabyte 970 gaming and i have 8gb ddr3 ram, before all this my r9 worked fine about 3 hours now, and i know the psu is small but still.