Question What would cause a computer to suddenly stop turning on completely?

[RobertWenger]

I've been troubleshooting my computer that will no longer turn on, and I need the opinions of others who are smarter than me. It does nothing when pushing the power button, and I have no idea why. Any advice would be greatly appreciated.

Where the problems started:
I recently needed to upgrade the RAM in my custom PC in order to play a specific game. I was originally running 2X8GB sticks, and upgraded to 2X16GB sticks. Upon swapping memory sticks, my computer appeared to work fine. The next day, when I turned the computer on, all the lights turned on and fans started spinning, but after about ~5 seconds the lights shut off and the fans stopped spinning. The ram was still illuminated (much like when I put the computer in rest mode), but pushing/holding the power switch did nothing. I needed to turn the PSU on and off, then push the power button, and the computer booted as normal. The next day, the computer repeated this cycle of shutting down mid-boot (with the ram sticks illuminated) and needing to cycle the PSU 5 times before it finally powered on properly. The day after that, I experienced the same issues and couldn't get it to actually boot without turning itself off. So I decided to take the memory back out and switch the positions, but the computer has never shown any signs of life since swapping the ram again. Pressing the power button now does nothing. The fans don't attempt to spin, and no lights appear on the motherboard, it may as well not even be plugged in.

My computer components are as follows:

• Motherboard: MSI MPG X570 Gaming Pro Carbon Wifi
• Processor: AMD Ryzen 7 3700X
• CPU Cooler: NZXT Kraken X73
• Old Memory: Corsair Vengeance RGB Pro 2X8GB 3600 MHz
• New Memory: Corsair Vengeance RGB Pro SL 2X16GB 3600 MHz
• GPU: Gigabyte GeForce 3080 Ti Vision OC
• PSU: Silverstone ST85F-GS (850W, 80+ Gold)
• Hard Drive: Samsung 970 EVO 1TB
• Case: Lian Li O11 Dynamic
• Fans: Corsair QL 120 RGB (Nine of these)
• Misc: Corsair Commander Pro (Fan power and RGB hub)

What I have tried to troubleshoot:

• My first thought was that I messed up the memory placement. I tried using one stick at a time, and both sticks together, with both the new and old ram. No configurations made any difference.
• I removed the GPU and re-installed, did not work
• I removed and reinstalled the CMOS battery, did not work
• I unplugged and re-seated all the power supply connections, did not work
• I swapped out the PCIE cables from my motherboard with ones that have never been used (they were the only spare cables I had for this PSU), did not work
• I removed the power supply completely from the case and "tested" it by itself outside the computer. I did this with a special connector that bridges the PSU-On and ground pins of the 24-pin connector, simulating the motherboard signal that tells the PSU to turn on. The PSU fan spun up fine, leading me to believe the power supply is good.

What I suspect is the issue:
I suspect the issue has to do with something hardware related. This computer worked perfectly for years before upgrading the memory, so it would make sense that I messed something up while swapping the components. Since NOTHING happens when pressing the power button (no fans spinning, no motherboard error lights, no PSU fan activity), I am suspecting the issues lie either with the PSU or the motherboard. I am not very knowledgeable regarding what to expect when pressing the power button, hence this forum post. I would imagine the computer would still "attempt" to turn on if certain components were bad, such as the gpu, ram, and hard drive, but I am not certain this is the case. Since nothing happens when pressing the power button, I wonder if either the computer is not getting power, or the motherboard is not communicating with the other components properly. I acknowledge that I "tested" the PSU, and it appeared to work, but I have seen other forums talking about PSUs delivering the wrong voltage. I am considering purchasing a PSU tester to measure the power output in order to rule out the PSU as a possibility. Otherwise, the only other thing I can think of that would cause the computer to not respond to the power button being pushed is that I fried my motherboard when swapping components.

Does everything described above lead you to believe the motherboard is dead? I was hoping to get some opinions from others before I spend money on a new motherboard. Any advice would be greatly appreciated. Thank you!

 

[Nine Layer Nige]

Have the ram slots been damaged or is there a bit of a foreign object found its way into the slot causing a short ?
Can you start the PC by bridging the 2 pins with a screw driver tip on the motherboard instead of using the on/off button on the case ?

 

[RobertWenger]

Have the ram slots been damaged or is there a bit of a foreign object found its way into the slot causing a short ?
Can you start the PC by bridging the 2 pins with a screw driver tip on the motherboard instead of using the on/off button on the case ?

As far as I can tell, the ram slots appear to be okay. I cannot see any foreign objects on the motherboard, but I could have missed something. If this were the case, is my only option to replace the motherboard? I just attempted to bridge the power switch buttons, and still no signs of life.

 

[Nine Layer Nige]

Try the JBAT1 jumper on your mobo, page 39 of the support manual
Resetting BIOS to default values
1. Power off the computer and unplug the power cord.
2. Use a jumper cap to short JBAT1 for about 5-10 seconds.
3. Remove the jumper cap from JBAT1.
4. Plug the power cord and Power on the computer.

 

[RobertWenger]

Try the JBAT1 jumper on your mobo, page 39 of the support manual
Resetting BIOS to default values
1. Power off the computer and unplug the power cord.
2. Use a jumper cap to short JBAT1 for about 5-10 seconds.
3. Remove the jumper cap from JBAT1.
4. Plug the power cord and Power on the computer.

Someone else instructed me to try this after I submitted my forum post. In hindsight, I should have posted an update to my forum, but thank you for doing that research! Resetting the bios via the JBAT1 jumper did not work. I also had a spare CR2032 battery, so I swapped that CMOS battery for a new one. This also did not work.

 

[SimTechPro]

Have you checked the power switch connector into the motherboard?

Can't tell you how many times I've accidentally disconnected it while tooling around in a case and thought I broke something.

 

[RobertWenger]

Have you checked the power switch connector into the motherboard?

Can't tell you how many times I've accidentally disconnected it while tooling around in a case and thought I broke something.

Yes, I have checked the power switch connectors. I experienced problems with the connectors when first building the PC, so I was concerned about them. But they appear to be fully seated into the correct pins. Jumping the power switch pins with a screwdriver also does nothing.

 

[SimTechPro]

Yes, I have checked the power switch connectors. I experienced problems with the connectors when first building the PC, so I was concerned about them. But they appear to be fully seated into the correct pins. Jumping the power switch pins with a screwdriver also does nothing.

I have had RAM that wasn't seated properly but still had lights come on. New RAM can feel like you're going to break it when inserted properly so people might be hesitant and not push it in all the way.

However, if you're 100% sure that the new RAM is seated properly then have you tried going back to the old RAM?

 

[Cellie]

If it has a speaker/buzzer you can also try to remove everything, RAM included, leave just the CPU and its cooler and the power to the mobo and CPU and see if it turns on and beeps a complaint. Failing to turn on then I'd also take the CPU out and try again.

 

[RobertWenger]

I have had RAM that wasn't seated properly but still had lights come on. New RAM can feel like you're going to break it when inserted properly so people might be hesitant and not push it in all the way.

However, if you're 100% sure that the new RAM is seated properly then have you tried going back to the old RAM?

Yes, I have tried going back to the old RAM. I even tried using only one stick at a time with both the new and the old set. No RAM or motherboard lights are turning on at all.

This is making me wonder if there is an issue with the motherboard or the PSU.

 

[Satan-IR]

Having to power cycle a PSU is sometimes the sign of a failing PSU, bad capacitors and so on.

Now that there's no sign of life as you put it, no fan no light, might mean the PSU is dead. You can take it out and do the paperclip test to see if the PSU powers on itself or not.

You can also if available check the PC with another equalr or higher capacity PSU to see if that's the problem.

 

[RobertWenger]

Having to power cycle a PSU is sometimes the sign of a failing PSU, bad capacitors and so on.

Now that there's no sign of life as you put it, no fan no light, might mean the PSU is dead. You can take it out and do the paperclip test to see if the PSU powers on itself or not.

You can also if available check the PC with another equalr or higher capacity PSU to see if that's the problem.

I have been able to test the power supply outside the PC, and it appears to work fine, However, all I know is that the PSU fan will spin when bridging the connectors with a paperclip, I am not sure if the power supply is supplying the correct voltage.

 

[Satan-IR]

I have been able to test the power supply outside the PC, and it appears to work fine, However, all I know is that the PSU fan will spin when bridging the connectors with a paperclip, I am not sure if the power supply is supplying the correct voltage.

Yes, that's just a test to ckeck if the PSU's totally failed/died or not. It's not a difinitive test of it's functionality in terms of being able to provide the voltages (3.3, 5 and 12) under varying and transient loads.

If you can test your PC with another known good, working PSU you can rule that out. Also by putting your PSU in another PC, if that other PC works with your unit that might point to the motherboard as you said before.

Have you tried resetting the CMOS after swapping RAM to new and back to old RAM?

Have you tried reseating/reconnecting all power cables from PSU to board and graphics card?

Also I would take the components outside the chassis to eliminate a possible short circuit. And I would breadboard with just MOBO + CPU + RAM (maybe even without RAM) outside the chassis to see if MOBO powers on and lights and so on. Do you have a speaker/buzzer connected to the motherboard?

 

[RobertWenger]

Yes, that's just a test to ckeck if the PSU's totally failed/died or not. It's not a difinitive test of it's functionality in terms of being able to provide the voltages (3.3, 5 and 12) under varying and transient loads.

If you can test your PC with another known good, working PSU you can rule that out. Also by putting your PSU in another PC, if that other PC works with your unit that might point to the motherboard as you said before.

Have you tried resetting the CMOS after swapping RAM to new and back to old RAM?

Have you tried reseating/reconnecting all power cables from PSU to board and graphics card?

Also I would take the components outside the chassis to eliminate a possible short circuit. And I would breadboard with just MOBO + CPU + RAM (maybe even without RAM) outside the chassis to see if MOBO powers on and lights and so on. Do you have a speaker/buzzer connected to the motherboard?

Unfortunately, I don't have another PSU or computer to use for testing purposes. It looks like I can get a PSU tester online for relatively cheap, so I may purchase one of these to rule out the PSU.

I have removed the CMOS battery, and have reset the motherboard bios using the reset pins.

I have checked all the connections, and they appear to be good. However, I have only been testing my pc inside the case. I may attempt these steps again with the motherboard outside the case. Thank you for that advice. I do not have a speaker/buzzer for the motherboard.

 

[SimTechPro]

Unfortunately, I don't have another PSU or computer to use for testing purposes. It looks like I can get a PSU tester online for relatively cheap, so I may purchase one of these to rule out the PSU.

I have removed the CMOS battery, and have reset the motherboard bios using the reset pins.

I have checked all the connections, and they appear to be good. However, I have only been testing my pc inside the case. I may attempt these steps again with the motherboard outside the case. Thank you for that advice. I do not have a speaker/buzzer for the motherboard.

If you don't think you'll be using a PSU tester in the future and you are prepared to replace the PSU anyway I would save myself a step and just buy a PSU to try out. If it fixes the issue then you keep it, if not return it and you'll be closer to your answer at least.

 

[Satan-IR]

Unfortunately, I don't have another PSU or computer to use for testing purposes. It looks like I can get a PSU tester online for relatively cheap, so I may purchase one of these to rule out the PSU.

I have removed the CMOS battery, and have reset the motherboard bios using the reset pins.

I have checked all the connections, and they appear to be good. However, I have only been testing my pc inside the case. I may attempt these steps again with the motherboard outside the case. Thank you for that advice. I do not have a speaker/buzzer for the motherboard.

Yes those buzzers will let you know if the board is alive and POSTing or if it is making error beeps, as said above.

Not sure if those testers check and let you know anything part from PSU being alive and the voltages at outputs. Nothing more. You would have more info than a paperclip test but that's it. Although if all voltages are what they're supposed to be at the outputs chances are the PSU might be OK.

If you decide to breadboard outside the chassis I'd suggest to look/check inside the RAM slots with good light and from different angles.

From what you described, looks like PC started having intermittent boots and then not even POSTing after you took new RAM out and inserted old RAM sticks back in the slots. The pins in the slots might be damaged/bent shorting. Or some debris in the slot shorting pins. Not very likely but not impossible either.