Question PC stuck in bootloop before POST

Dinter

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May 4, 2013
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Hi.

One of my friends' PC was working fine, when they tried to open Youtube and it turned off as they said. Since then it's stuck in a boot loop before even POST. When I try to turn it on nothing appears on the screen, it doesn't even notice that the PC has been powered on.

First, I removed all the USB devices. Then tried plugging off the PC, reseting CMOS, CMOS battery, pressing power button for 30 sec. Then I removed the GPU as well and left only 1 RAM of 2, tried in different slots. Then I reseated the CPU, put new paste on it, reseated the cables. Now there's only the PSU, MOBO, CPU and RAM put in.

If I remove all the RAM's, it beeps signalling that it's missing, however, if I put one back, it gets back to the loop again.

What could be the problem? Mobo, PSU, or CPU?
 

Dinter

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May 4, 2013
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Okay.

Ram installed: pressing power button, fans power up, green led on the case lights, after like 5 sec led goes out and fans stop spinning. 2 secs later it starts up again. This in loop.

No ram: pc starts, fans spin, green led stays, and constantly beeping because of the ram. No loop, powered up until I shut it down.
 
Did your friend have any kind of power outage or something similar when this started? This sounds like it could be multiple issues. The poweroff from youtube no warning is a sign that would point to a PSU or temp issue, though most modern hardware will throttle long before a sudden shutdown. Possible the PSU is failing and damaged other hardware with it. The PC staying on with beep codes with no RAM installed or power cycles with either stick in any slot is quite odd in itself if it were only PSU. I've personally worked on a system with a Z87 MSI board awhile back that a slot went bad, and any RAM stick installed in that slot would cause power cycling. Either stick in any other slots worked fine. The slot "went bad" somehow. Do you have any other RAM available that is correct type to test with? For that matter, can you provide full system specs?
 
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Dinter

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Tomorrow I will test it with another PSU and RAM and will post the full spec


Afaik there wasn't power outage or something similar since we live few houses apart, but I didn't ask it. Hopefully clearer after the test with other PSU and RAM.
 

Dinter

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So the thing is I tried it with different, working RAM and PSU but it's the same. It can be only the mobo then, can't it?

Spec:
PSU: Chieftec GPA-450S
MOBO: Asrock B75-Pro3M
CPU: Intel i5 2400
RAM: Corsair cmz8gx3m2a1600c9
 
Thanks for the update. It's possibe the PSU took the board with it if it was faulty. Since you tried working RAM and PSU with same result, then yes it is most likely the motherboard. CPUs themselves rarely fail. Is the "test" RAM tried in each slot individually? Is it on the QVL from ASROCK listing on their site for compatibility? Some boards can be picky on modules.
 

Dinter

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Yes, I tried it in each slot and it's compatible.

You're saying the PSU is surely defective, not only possibly the motherboard?

I forgot to mention there are some rinses missing in the case under the mobo. Is it true that it can bend it on the long term?
 
rinses? Are you referring to motherboard standoffs? All standoffs that contact the board should have a screw securing them properly. However, certain boards may not have the middle standoff in standard ATX boards. Using that setup myself with my current Intel board as I can only use 8 standoffs. I'm doubtful a single missing standoff in any area is a big deal, but more than one, may cause an issue over time depending on weight(CPU cooler or GPU). The PSU may still have issues, as you described in the original problem, as shutoffs without warning is a common symptom. However, you would need another motherboard at this point to test based on info thus far.
 

Dinter

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Okay so updates.

I got a hint to try pressing reset button when it turns on. This way I managed to reach the BIOS twice and I flashed it. However after the flashing it's still stuck in the boot loop. What now?