Been having an issue with my monitor which originally led me to believe it may be due to using my old hd TV as the main monitor. turns out, having tried another PC monitor, that the issue is a bit more random. When I start my PC up from having been off, and shut down, it loads up to the point where the next screen would be the login. However, it for some reason, the screen goes black as if the cables been pulled out. Also, the mouse, keyboard, controller and any other peripheral device attached to the PC loses power. It's as if all the ports just stop working. The only way for me to get the computer back to its normal self is to physically turn it off at the plug and wait a few moments until the powers gone form it. Once I start it up, everything works fine. Any ideas on what could be causing this?