Broken ram slot?

Hi, My cousin has a Alienware 15 r3. On Black Friday sale he bought a hyperx ddr4 sodimm 2666mhz 2x8gb ram stick USED(Very Good) in Amazon. We installed the ram stick and then started playing PUBG. While playing the laptop BSOD with memory issue(forgot the error code was not able to take note but sure it was about memory).
We decided to run a dell built in diagnostic test and memtest.
Dell diagnotics all passed but memtest had an issue. One part of the test causes the laptop freeze. Tried it 3 times but same result. Certain part of the memtest causes the laptop to freeze.
Decided to put the hyperx ram stick to my laptop and run memtest. On the part of the test which causes my cousins laptop to freeze, it did not happened on mine. It passed that part of test. We did not fully completed the memtest in my laptop as it takes hours. We got his Hyperx ram stick and put it back on his laptop. Suddenly get a error beep light codes which was ram not detected and also RTC Failure.
We cleared the CMOS right away via shorting the CLRP1 pins.
Assembled everything back and still the same problem occurred.
This time we did a power drain and cleared the CMOS.
The laptop booted up and ram was detected(thought it was all sorted due to clearing CMOS).
We decided to do a BIOS update because the bios of his laptop was never updated since he got it. His laptop's bios was version 1.1.8 which was not listed in dell website and thought that might be the issue.
Updated his bios to version 1.1.9 with the hyper x ram in it.
Then we did another dell diagnostic test thinking that the hyperx ram was all good as it ran OK in my laptop.
Now the laptop freeze during the dell diagnostic test.
Manually rebooted the laptop and we had the light beep codes again but this time only indicating ram not detected. BACK AGAIN TO THE PROBLEM.
We just decided to turn off the laptop and let it rest.
After a few hours we tried to turn it on and this time it booted again detecting the 2x ram stick but after a few hours the laptop freeze again.
Manually turned the laptop off.
We then thought we will just to the put on the original ram stick(only 1x 8gb). The laptop booted and got it running again.
We decided to return the hyperx ram stick to amazon as we thought it was dodgy due to being a used product.

Bought a new Crucial ddr4 sodimm 2666mhz 2x16gb.
Installed the new Crucial ram stick and we got the error beep light codes indicating ram not detected.
This time we are suspecting what if the problem was the ram slot.
We tried each ram stick on each slot 1 by 1 and found out that 1 ram slot is not detecting the ram stick showing the light beep codes.
My cousin is now only using 1x16gb ram stick and the laptop is working as of the moment.
Questions:
- Is that one ram really slot broken?
- Was it already faulty every since he bought the laptop as we never had a chance to test it out until now?(Problem as well as we cant remember which slot the original ram was placed and really unable to determine if it was the unused ram slot)
- Or doing the shorting of CLRP pins and did not do a power drain first fried something in the motherboard or maybe busted a capacitor?
- Maybe static charge did something to the motherboard?
- How come at some point both hyperx ram stick was detected and now we cant work the 2x ram stick at all? Was even able to do a bios update.
- Maybe a busted capacitor was slowly broken and not working which is why we can work the 2x ram stick?
- Could it be related to BIOS and his BIOS needs to be updated to the latest version?
- Also could the hyper x ram damaged the ram slot/motherboard?

Note:
We have tried cleaning the ram sticks gold pins with alcohol and microfiber cloth but not cleaned the ram slot as we don't know how to do it.
Also in the process of getting a compressed air can to blow off the ram slot in case of dust.
Afraid of fully disassembling the laptop as of the moment as we might break something again.

Sorry for the long read and bad english. Hoping someone can help us figure this out. Thanks in advanced.

 

Just to be sure, you have tested the new sticks one by one? You should use memtest86 in multi-thread mode, it's not *that* slow and it tests it extensively.

But you're saying they're not being detected at all in one slot. Very rarely, some RAM just won't work, see the manufacturer of the RAM chips themselves - are they the same as the original stick?

You could try updating the BIOS (using your good RAM!), it's worth a try.

The only other thing I can think of is use another CPU - if the RAM works fine then it's the memory controller, if not, it's highly likely the system board has some fault between the CPU and the RAM (could be the traces or the slot).

So, in order of probability, in my opinion:

Incompatible RAM - try something from a different manufacturer (of the chips, not the module, i.e. Micron, Samsung, Nanya, whoever else makes chips these days)

Faulty RAM (and really bad luck) - try another pair, one that you know works 100%;

Faulty system board/slot or Faulty memory controller - if you try another CPU with the same RAM, you can narrow it down between these two.

 

Thanks for the reply.
The laptop is a Alienware 15 r3 which is a BGA laptop. Meaning CPU and GPU are all soldered.
About the RAM Sticks. The crucial are the new ones which 100% sure worked on 1 ram slot only. We also have the original ram stick that came with the laptop and 100% sure worked on 1 ram slot only.
The other ram slot which is the problem doesn't work as the laptop cannot pass POST as it will indicate a beep error code which means Ram not detected.
We are leaning/believe that 1 ram slot is not working at all which might be a system board failure.
The question though is that it originally worked with the hyperx ram stick then gradually not working at all.
Does a faulty ram stick(thinking the hyperx) cause such problem making 1 ram slot not to work at all?
Did we caused the problem that we fried the motherboard at the same time changing the ram stick? Like static discharge or when shorting the CLRP1 pin to clear the CMOS fried the system board or something.
If it is a system board issue, can it be fixed by a average person?

 

It worked but it crashed, right? It does seem like a memory controller/system board fault.

It could be a case where it would detect a module once in a while (maybe only when it's cold or hot, or when the BIOS was reset)...

 

Gotcha..
Is it fixable?
If we will just ignore that broken ram slot and can live with a 16gb ram stick. Would the system board be just fine or will it gradually die on us?
Our issue is that when we had the laptop we never had a chance to test it with 2 ram stick.
Is there a chance that the laptop came with a faulty system board already?
From my perspective I don't believe it was a Electronic Static Discharge that cause the problem as we were wearing protective gears to prevent static discharge. Wut a bad luck this is.

 

I don't know if it will have more issues or not. It's likely a factory fault and it would have to be replaced completely. Is it still under warranty?

I also doubt an ESD could've damaged something, I've handled a lot of laptops and computer parts, never had a problem.

 

Out of warranty. Dang. Anyways thanks for clarifying things for us. Will just hope no issue will occur. It survived years with 1 ram stick anyways.