Question PC won't boot, fans won't turn on, no diagnostic lights. Desperate for help!

[Kentone]

Issue

• Newly built PC was working fine for a month then suddenly would not boot, no fans, no lights, nothing
• Replaced PSU and motherboard thinking they were the issue, no change, still can't boot, no fans, no lights, no motherboard beeping
• Now I only have the PSU, motherboard, CPU, and CPU cooler installed, with the PSU motherboard and CPU connectors attached to the motherboard, the motherboard outside of the case, on top of the non-conductive box that it came in, but I still can't even get the fans to turn on
• A PC repair store thinks the CPU could be the problem but I've read online that even if the CPU was an issue, the fans would still run and I would get a CPU diagnostic issue from the motherboard, trying to RMA it because I'm at a loss on what else to do

Attempted Solutions

• Replaced PSU and motherboard after taking to local PC repair shop to diagnose issue
• Rebuilt computer three times in case a connection wasn't fully plugged in
• Reset CMOS
• Capacitor discharge
• Tried to short power pins to turn PC on in case the power button was faulty
• Removed all fans and case connections in case faulty fans or case was causing a short
• Removed GPU, RAM, and SSD in case one of those components were causing an issue
• New: successfully flashed to latest BIOS using the motherboard's BIOS flash button thanks to Steve's suggestion below

Components in case relevant

• GIGABYTE B650 AORUS Elite AX V2
• Corsair RM1000x Shift
• 9800x3d
• Thermalright Phantom Spirit

Full Context

About a month ago I finished building my first computer that worked perfectly fine until about a week ago. It was on, had a chrome browser on, put it to sleep, walked my dog for about half an hour, came back, went to turn it on and nothing would happen. No fans turning on, no beeps from the motherboard, no diagnostic lights. I flipped my PSU off and on and the RBG lights on the motherboard that were previously disabled turned on but that was all I could get.

After googling it up and trying a bunch of troubleshooting steps, I could not resolve the issue so I brought it to a highly rated, local PC repair store. They took a look at it and determined that the PSU and motherboard were dead and needing replacing, they said likely due to a power surge. I have my PC plugged into a surge protector, along with my monitor, speakers, and work computer, and none of them have issues, and there's no other signs of a power surge in my house (typically clocks reset?) so I'm not sure if that actually happened but they said their benchmarks showed the PSU and motherboard definitely needed replacing, maybe more components but they couldn't be sure.

I went out and got a new PSU and motherboard, different models and brands just in case there were some weird interactions with my combinations of parts. Rebuilt the PC, exact same thing is happening. No motherboard diagnostic lights, no beeping, no fans turning on. The only thing that happens is the motherboard RGB flashes on when I flip on the PSU. I called the repair shop back and now they think it's the CPU that's the issue.

I am going absolutely crazy not being able to understand what is wrong, thank you very much in advance for any help or perspective!

 

[DaleH]

Issue

• Newly built PC was working fine for a month then suddenly would not boot, no fans, no lights, nothing
• Replaced PSU and motherboard thinking they were the issue, no change, still can't boot, no fans, no lights, no motherboard beeping
• Now I only have the PSU, motherboard, CPU, and CPU cooler installed, with the PSU motherboard and CPU connectors attached to the motherboard, the motherboard outside of the case, on top of the non-conductive box that it came in, but I still can't even get the fans to turn on
• I called the PC repair store back and they said that the CPU could be the problem but I've read online that even if the CPU was an issue, the fans would still run and I would get a CPU diagnostic issue from the motherboard

Attempted Solutions

• Replaced PSU and motherboard after taking to local PC repair shop to diagnose issue
• Rebuilt computer three times in case a connection wasn't fully plugged in
• Reset CMOS
• Capacitor discharge
• Tried to short power pins to turn PC on in case the power button was faulty
• Removed all fans and case connections in case faulty fans or case was causing a short
• Removed GPU, RAM, and SSD in case one of those components were causing an issue

Components in case relevant

• GIGABYTE B650 AORUS Elite AX V2
• Corsair RM1000x Shift
• 9800x3d
• Thermalright Phantom Spirit

Full Context

About a month ago I finished building my first computer that worked perfectly fine until about a week ago. It was on, had a chrome browser on, put it to sleep, walked my dog for about half an hour, came back, went to turn it on and nothing would happen. No fans turning on, no beeps from the motherboard, no diagnostic lights. I flipped my PSU off and on and the RBG lights on the motherboard that were previously disabled turned on but that was all I could get.

After googling it up and trying a bunch of troubleshooting steps, I could not resolve the issue so I brought it to a highly rated, local PC repair store. They took a look at it and determined that the PSU and motherboard were dead and needing replacing, they said likely due to a power surge. I have my PC plugged into a surge protector, along with my monitor, speakers, and work computer, and none of them have issues, and there's no other signs of a power surge in my house (typically clocks reset?) so I'm not sure if that actually happened but they said their benchmarks showed the PSU and motherboard definitely needed replacing, maybe more components but they couldn't be sure.

I went out and got a new PSU and motherboard, different models and brands just in case there were some weird interactions with my combinations of parts. Rebuilt the PC, exact same thing is happening. No motherboard diagnostic lights, no beeping, no fans turning on. The only thing that happens is the motherboard RGB flashes on when I flip on the PSU.

I am going absolutely crazy not being able to understand what is wrong, thank you very much in advance for any help or perspective!

If I had this problem, I would still suspect a power problem. I would use a voltmeter to measure the power supply voltages using the info at this site to know where to measure and what it should measure. Post the results here. If you have a new PSU, it is probably not the culprit. One commonality, is the power switch on the case.

 

[Kentone]

Thanks for the quick response Dale! I will try and get a voltmeter or ask the PC repair shop if I can take it back and use theirs just to fully confirm.

Right now the only connected parts are:

• CPU installed into motherboard
• CPU cooler installed on top of CPU and connected to motherboard
• PSU connected to motherboard through the ATX 24-pin (motherboard plug on motherboard) and the ATX 8-pin (CPU plug on motherboard)
• PSU plugged into a known working outlet, and turned on

I wanted to eliminate variables like the case power switch so that isn't plugged in, currently trying to boot it up just to get fans and diagnostic lights going by using a handy power-on switch this particular motherboard has, and by shorting the power pins by connecting the two power switch (PW+ and PW-) pins together with something conductive.

 

[steveb1976]

the 1 quick way you can test is to try and do a bios update.. using usb stick and the flashback button on the back of the motherboard...

if the flash starts up then the motherboard is getting power and could even kickstart the pc back to life. not promising this will work 100% but ive had luck 2 times out of 3 boards that did this .. its worth a try ..

take cpu out and just use "8pin cpu" and "24 pin power"

 

[Kentone]

I took out the CPU, put in a flash stick configured with the latest BIOS, hit the BIOS flash button on the motherboard, and the CPU diagnostic light comes on for a second or two and goes off.

The motherboard user manual says that the BIOS flash LED should turn on and flash until the BIOS update is completed. The BIOS flash LED does not turn on at all, only the CPU diagnostic light flips on for a sec.

I tried reinstalling the CPU just in case that would help, but tried it again with the CPU back in and the same thing happens: press BIOS flash button, motherboard CPU light (and the light on my usb stick) turns on for a second or two, then turns off.

Could I have gotten a brand new, defective motherboard?

 

[steveb1976]

if it turned on and then off after a few seconds. then either the motherboard does not like the usb stick. or it was not formatted correctly or the file was not renamed correctly. . i have to keep 3 usb sticks handy when im bios flashing peoples boards. some motheboards are fussy..

 

[Kentone]

Tried another USB stick and it flashed successfully, thanks!

Tried to boot again after using the motherboard's boot button, and by shorting the power pins together, and still no action - no diagnostic lights or fans turning on, but does the BIOS flashing at least mean the PSU and the motherboard are working properly and are not the issue?