I have a desktop computer with a gigabyte GA-870a-UD3 motherboard, AMD Phenom X6 1100T CPU, xtremegear XG-P700 power supply, GTX460 graphics card.
Symptoms:My problems started yesterday, when I tried to turn on my computer after not using it for a week. It wouldn't boot, sometimes freezing at the BIOS splash screen, sometimes not loading the BIOS at all but the fans just whirring, sometimes taking a long time to load the BIOS, but eventually doing so and booting fine. Once it froze at the windows login screen, and it also sometimes booted up normally. However, after a couple hours of gaming, it froze. I took off the case and laid my computer on its side, as it previously had issues overheating. This seemed to make it boot up easier, and when I put it upright and closed the case, it wouldn't boot. at one point I put the computer upright while it was on, and this caused it to immediately crash. While it was working, I did get I chance to monitor the temperature while I was gaming, and it did not seem excessively high (45C while idling, 60C while gaming. my previous problems were due to crashes at exactly 62C, but I had since fixed a motherboard setting and it had operated at well above 62C without any problems). Today, I have tried to get it to turn on several times, and the best I have gotten is freezing at the BIOS splash. It still seemed to be sensitive to being upright vs on its side, but at this point it's deteriorated to the point that nothing I can do will make anything happen beyond turning on the fans.
What I have tried:I have tried removing the CMOS battery and replacing it.
I have tried resetting the BIOS using the jumper pins according to the instructions in the motherboard manual.
I have tried reseating the RAM and GPU, as well as disconnecting and reconnecting all the internal connections.
I have tried disconnecting everything (including all power) from the motherboard except the keyboard (my keyboard has a light on it which turns on when the BIOS loads)
I've tried disconnecting everything except the GPU.
I have tried testing the power supply using the paperclip method: the power to the motherboard and GPU are all well within the tolerances.
I have looked inside the case and shaken it up for any spare parts causing shorts
throughout all of this, I have gotten exactly the same result: power on causes fans to spin, and the power button light to turn on, and absolutely nothing else. The power button will work if you hold it for 5 seconds, and that is it.
What I think I have ruled out:I don't think it could be a problem with any of my drives, as nothing works even when they are completely disconnected
I don't think it is my keyboard as the light on my keyboard was still turning on even when my computer froze at the BIOS splash screen, and it still doesn't load at all when I disconnect my keyboard.
I don't think it's my RAM, as it still wouldn't work when I removed all my RAM
I don't think it's my videocard, as my USB keyboard will not light up even when the GPU is removed.
I don't think it's my power supply as I checked all the voltages and they are correct.
At this point that leaves me thinking it's something wrong with my motherboard or CPU.
Any help at this point would be appreciated.
Also, one last thing, my computer does not beep at all when turning on. One of my drives did when it was connected (even when the BIOS wouldn't load) but the stripped down system does not make any beeping noises (which I know can be error codes).