I have recently built my own pc (for the first time). I am pretty sure it is built correctly but after launching it for the first few times am worried that i have wasted my money. When i turn it on it beeps once and brings up the boot screen as usual. If i leave it, it brings up a black screen saying "reboot and select proper boot device or insert boot media" which apparently is normal. The problem is that when i try to access the boot menu/bios when i first turn on the pc, the screen goes black (fully with no text) and soon stop displaying video to the monitor altogether- almost asif the moniter has turned off. i have tested it with mutiple moniters and hdmi cables- HELP PLEASE. I DONT WANT TO WASTE ABOUT £500