I bought an i5 3.1GHz and 8GB RAM as well as an Asus P861 Motherboard recently. It was working fine for about 2 weeks, then last Sunday it didn't give any display or beeps. I tried a lot of things, barebones startup, etc, but nothing. I thought it was a problem with the power supply (I had 500W) so I bought a Coolermaster 750W. Yesterday when I put in the new power supply, it started up fine, but then but I hadn't plugged in one of the hard disks so I shut down the PC again and it started giving the same old problem. I tried switching out hard disks, RAM, VGA, resetting BIOS, everything. Nothing happened.
Then this morning, when I turned the PC on it turned on without any problems. It worked until about 3.30 when we had the power cut. I tried turning it on again at about 6pm then it gave the same problem. I took the whole motherboard out and changed the screws, but still nothing has happened. It turns on, the fans spin, everything works but no display, no beeps.
I should also mention that I had the exact same problem on my old Core 2 Duo + Asus P5QPL Motherboard. I upgraded to the new specs because that problem was getting out of hand. I am so frustrated that the same thing turned up on the new hardware as well. I have no idea what to do. Any help or insight in to this matter would be highly appreciated.
Try changing out the VGA cable, it might be cause a problem, if not, try shoving ram into the slots one at a time.
Also if it does this again, Try unplugging the power cord from the psu hold down the power button for 10 seconds to let all the Capacitors drain plug her in and power on. sometimes works sometimes doesnt. I know most of the time it worked for me
Try replacing (if possible) all the things that remained a constant between the two builds. you've already replaced your PSU, CPU, mobo, RAM, HDD, etc., so lets knock those out. Have you replaced the GPU? have you replaced power cables, power strips, tried different outlets, etc.? I'm just wondering if it's a true power issue, like maybe the wall outlet or something.
Thanks for all the great answers guys. dextermat was right, it was a faulty motherboard. I RMA'd it and they gave me a new one within 15 minutes. Amazing!
I also replaced my UPS and discovered an interesting fact: My old UPS was faulty, and our power grid is also somewhat faulty. There are frequent drops in power around 1-2am in the morning. The lights don't even dim, but the new UPS switches to battery frequently. Sad that I had to burn two mobos before I discovered the actual problem.