I've just bought a gigabyte motherboard computer, GA-F2A78M-D3H, and it says that I need to reboot and select proper boot device, so I researcher end the problem and found out that I had to press DEL at the start of turning it on to take me to the setup page, or F12 to take me to the boot page, but each time I do either it just takes me to a black screen with only the mouse and nothing else. Can anybody help?