I've had my current computer build for about 6 months now and it had always operated perfectly. A couple of weeks ago, my computer began to power off spontaneously; no BSOD, no errors and no beeps. The system would merely shut off completely out of the blue. I would turn the system back on, and it would boot up and operate fine. After this happened a few times, my system refused to boot. Following is the progression of the symptoms and steps I've taken thus far:
Initially, pressing the power button did absolutely nothing. Pressing the power button didn't get any response: the CPU fan wouldn't spin up, none of the activity lights would come on, and my HDD's didn't make any noise. After opening the case up, I noticed that when attempting to power on, my CPU fan would twitch on the initial push of the power button and then nothing more would happen.
I then disconnected all of my peripherals (video card, network card, HDD's, DVD's) and left only the CPU, RAM and PSU connected and attempted to boot. When I pressed the power button, the PSU fan spun into action, and the CPU fan appeared to be struggling to spin for about 2 to 3 seconds (yes, it was clear of dust and hair) and then finally spun up into action. However, there was no activity on my monitor (was plugged into on-board video), no lights on the keyboard, the system wasn't POSTing, and I lost functionality of my power and reset buttons (could only power the system down by flipping the switch on the back of the PSU).
I re-connected one of my HDD's and powered on again, and I can very clearly hear the HDD spinning into action, but again, no POST, no beeps, etc. I made the assumption that my PSU had died, so I bought a new one. Unfortunately, the problem remained the same. I have a spare motherboard that I tried, and the same exact symptoms. I also have a spare case that I tried (thinking maybe my power/reset buttons were fried), but still the same symptoms. I tried using each of my two RAM sticks individually in the first slot, and even trying to boot without any RAM, and I received the same symptoms: no POST, beeps, keyboard, video and no power/reset button functionality.
So at this point, I'm fairly confident that I either have a dead CPU or RAM. I'm on a fixed income and tight budget and already wasted over 100 on a new PSU, so now I'd like to be absolutely sure of the problem before I go purchasing more replacement parts. So in summation, the symptoms are that the computer turns on and the PSU fan, CPU fan and HDD all power on normally; however, the system will not POST, there are NO beep codes, there is no keyboard activity/response, the power/reset buttons do nothing and I have to turn the system off by flipping the PSU switch.
I'm leaning towards the problem being my CPU, seeing as neither of the RAM sticks affects the symptoms, and it would be unusual (although possible) for both of them to die so suddenly. I appreciate any input and suggestions offered. Thank you all in advance.
P.S. I have no problem posting the specs of my hardware, but given that I've tried two different motherboards, PSU's and cases; and furthermore given that the system ran fine for 6 months, I'm doubtful it's an issue with hardware compatibility. This post is already lengthy enough, but if something believes it may be helpful, I have no problem replying with the system specs.
No need for System Specs you are ignoring one of the first signs. and that is the Fan for your CPU was going, the fact that the PC shut down with out warning as you say, tells me you overheated the CPU, By way of a bad fan. putting it on another MB rules out anything else. You handled the diagnoses perfectly but are ignoring your Prognosis.
I had the same problem but concluded that somehow I had a "case short" which shorted out 2 motherboards. I bought a new ASUS M3A78 and built another quad core backup with Windows Vista. Smooth install! I decided to bring the board to my brother to upgrade his quad system. I shut down his computer and took out his ASUS M3A and installed the ASUS M3A78 and no signal to the monitor. I took the board out and put his ASUS M3A back in and again no signal to the monitor. I did an out of the case benchtest on cardboard testing both boards (minimal "barebone" setup) each with an AMD X4 9850 cpu, antec earthwatt 500w p/s and a brand new Rocketfish 550w p/s, 4 sticks of crucial pc2-8500 (1066mhz) ram (1 stick at a time. 2 sticks was his and 2 were mine and all worked), an ATI 4830 and a Sparkle (Nvidia) 9800gtx+ video cards. After doing all the tests and configurations, there was still no signal to the monitor! I took the cpu and the ATI 4830 video card and installed it in his backup computer which has an MSI board and it fired up beautifully and smooth! All motherboard risers were in place for the appropriate boards in the case. I've concluded after all tests that somehow (still trying to figure it out) the case has a "case short" and took out both motherboards!
either psu or mother board is not grounded and shorting out. check all your wires make sure no insulation has been damaged and all connections are right.the worst thing you can do is not have your main board on brass spacers.remember the the capasitors on the main board and every other component for that matter emit's discharge when need and something as small as that could have done it.
long story short I think you dont have your mainboard grounded properly and this would cause the cpu not to start.Do this to many times and you will fry the psu or mainboard.
I had the same issues, and it turned out to be the CPU. I would RMA the CPU. I RMAed my mobo first, and it came back with an OK. I would say it's definitely the CPU.
However, if you want to do something before that, you can try hooking up the system out of the case. I know I read a lot of things about the Antec Sonata and a static-prone front-panel. It might be worth a try, but it's probably the CPU, yeah.
Sorry to hear your troubles. I can't believe what a frustrating experience it was for me to find the problem.