After receiving a new motherboard I wanted to start from scratch so I start to erase all my files from my pc but when my pc was on about 35% the power went out and now the pc won't turn back on. When I press the power button all fans spin and light come on and I hear a beep a couple of seconds later there is a long continuous beep which doesn't stop and the screen is aslo black with a with flashing underscore in the top left corner. Can anyone help?