This isn't the first time this has happened. I went to the store and left my computer on, but when I came back, my display was black. This also happened a few days ago after our power flickered, I turned the computer back on, but it wouldn't display anything. In the past when this has happened, if I flipped the switch on the power supply, then turned it back on, everything would run like normal. This time, however, it's not coming back on. The computer POSTs just fine, I've tried different cables and monitors, but still nothing. My friend had this issue a while back too, but after his computer sat off for a while it ran just fine.