Computer: HP Pavillion Elite e9120f w/ no upgrades Monitor: HP w2338h connected via HDMI Receiving "no signal input" message on monitor. All of the following actions have been taken and problem persists. Switched HDMI cable. Switched to VGA cable. Switched monitors, switching to both HDMI and VGA connections. Replaced external video card with new external video card. Attempted safe mode start. Computer is used exclusively by my 16 year old son. So, hard drive is filled with what I call "crap programs". On restart the computer beeps just once. Suggestions?