Okay, so a while ago I finished building my new Pc. It was working fine for about 3 days but then it would randomly go black and show the message, "Please select a proper boot device and press a key". Prior to this I had accidently been turning off the power to my computer (it was in a weird position, so when i stretched i would kick the cable). Could having turn off the power caused this? I only did this twice. I also tried connecting it to different sata ports and nothing. This was my first built pc and I really need help. Thank you.