Hello, my quite old Dell pc has an intermittent issue. It will be running fine for weeks and then suddenly not post or boot up. The power light comes on but no fan nothing. I took it to a repair shop and they spent days trying everything they could think of. New power supply, changed out the memory…. They finally concluded my dvi monitor port was the issue. So I just removed my second monitor. It ran fine for days then again no startup. I found a solution that works every time but I do not know why. If I unplug the computer for 30 minutes, then hold the startup button for 20 seconds to clear the CMOS, and replug the power cable it starts perfect…..until a few days or weeks later when it happens again. Any ideas what is causing this. I assume they checked the CMOS battery. But you never know. Could that be the problem?