Computer won't boot all of the sudden - debug LEDs point to CPU/RAM

Hello guys, I'm trying to help a friend remotely so I'm writing this as if it's my PC.

So I tried to turn on my PC today. It turns on for a second and then turns off. I didn't know what's up so I tried to debug it by making sure everything fits into place. Still no go.

I pulled my RAM out, both of them and it seems to keep on booting. So I kept only one stick which I moved between both slots. Seemed okay so I plugged in the other one, then it stop booting. So I plugged everything back in, leaving the faulty stick out but the PC won't POST. My keyboard's backlight was blinking, the mouse as well, seemed like something at fault.

I looked at my Mobo again and saw there are debug LEDs. I have an MSI Z270 pc mate motherboard and according to their website, and if I understood the following sketch correctly, my CPU and DRAM was bad:



The top 2 LEDs are lighting up when I turn on my PC. I tried to move the only working stick I had to another slot but that didn't fix the issue.
I also tried to unplug everything from the power and hard reset my computer by holding down the power button for 30 seconds.
I'm afraid to try and reinstall the CPU, is it something that can be done by anyone?



I have this computer for 3 years and never had an issue.

This is my rig:
MSI Z270 pc mate
I7-7700
VENGEANCE® LPX 16GB (2 x 8GB) DDR4 DRAM 3000MHz C15 Memory Kit - White
Antec NE650M
GTX 1070


Any help would be great.

- - - Updated - - -

Apparently, pulling out all RAMs leaves just the RAM LED on, the CPU one is off.. Does that indicate a RAM issue?

Ghot said:

@BDani


Just to get you started in your trouble shooting... the computer needs at minimum, one stick of RAM.
The motherboard manual, will tell you which slot it needs to be in.

Manual: Support For Z270 PC MATE | Motherboard - The world leader in motherboard design | MSI USA


For only one stick of RAM it goes into the 2nd slot counting away from the CPU (left to right).

Yeah, thanks :) So with both of them, it turns on then immediately off. With one of them, it's the same, with the other one, it turns on just fine but those LEDs are on and the PC won't post. I wasn't sure whether taking both of the out would still show both LEDs on, so I gave it a try :)

Ghot said:

Think more like a computer.
When you take both out... the motherboard sees missing sticks as bad sticks. To the computer missing = broken.


As to fixing this issue, what was the last "hardware" thing the friend was doing, before the problem?


Some things to consider...

The CPU LED being on is not good. On some motherboards, there MUST be a fan plugged into the motherboard CPU-Fan header for the CPU to even TRY to start.
Then there's the thermal paste, and possible bent pins on the CPU.
Also don't forget the CPU power connector...usually top left of the motherboard.

For the RAM... try each stick one at a time in the 2nd slot away from the CPU.
Make sure you've reset the BIOS to defaults. ALWAYS do that when troubleshooting a computer.

Thanks :)
We tried to reset the CMOS, the working stick of RAM was indeed in that 2nd slot from the CPU and he unplugged and then plugged the CPU power connector but still the same issue.
I didn't want to ask him to reseat the CPU because he has no thermal paste to reapply, or even alcohol to clean the existing paste. He's off to another friend to borrow his RAM. We have our fingers crossed. Otherwise, it might actually be the CPU, who knows.

These links have beep codes and troubleshooting steps that may be useful:

What is POST?
Computer POST and beep codes
POST troubleshooting steps

Ghot said:

If he hasn't tried to remove the CPU cooler... then you can probably rule out a thermal paste issue or a bent pins issue.
Double check if the CPU fan is plugged into the CPU_fan header on the motherboard. Usually up near the top left of the RAM slots.
There might be two CPU fan headers or even three. make sure that a fan is plugged into the CPU_Fan, and not JUST one of the other two.

Also.. get a list of his actual components (make/model).
Mainly the motherboard, CPU, RAM, CPU cooler, vid card and power supply.


For example... if the CPU cooler is an AIO water cooler, we need to know that. They could have a bad pump, for example, which would mean the CPU would heat up so fast, that the computer might not boot.

Again, probably the most important thing is the "history" of what he was messing with BEFORE the computer stopped working.

Was he trying to flash the BIOS?
Was he trying to change the thermal paste?
Did he pull the RAM sticks out, w/o shutting the power off first?
Etc., etc., etc.


Also, never forget that flexing the motherboard too much can crack a circuit run.
Things that flex the motherboard, would be things like...
Pushing too hard when installing RAM, or the vid card.
Doing something with a screwdriver, when it slips and bashes the motherboard. Etc.



/edit
You might also want to see if you can boot from... anything. Like a bootable CD or USB stick. With the CPU led ON, I doubt you will be able to, but it's easy to check.

So the case has little stubby legs. He claims to have moved the PC a little forward so the front legs were not sitting on a flat surface anymore and the bottom of the case got a hit from the surface on which it was sitting.
Here's an illustration I made lol:


So number 1 was moved forward (the case's legs) and the underside of the case (num 2) got hit. He says it wasn't like the computer fell but that's what happened.

There is no OC, the CPU has fans.
Also, he just replaced the RAM so that's not it I guess.
Other than that, the computer was never touched, moved or meddled with.

I'll check the CPU fan thing with him. Thank you for the help!

- - - Updated - - -

Ok so he has a NH-U12S - Noctua CPU fan. I don't know if it sounds plausible but here's my theory:
When he hit the PC case, the weight of the CPU fan bent a pin in the CPU.

We just inserted both sticks back and it stopped turning on and off on it's own, now we're simply left with no POST.
I'm guessing it's the mobo or CPU.

By the way, all the fans spin and everything looks okay. So I'm out of ideas so far.