Just acqured a used Alienware Desktop Computer and it won't power up
 

Hello everyone, yesterday I went to my local computer store/electronics recycling place and I picked up for $10 an old (2016) Alienware Desktop computer that I wanted to monkey around with and see what all the hype was about with them (and so I could have an extra computer if my main one goes down.)

When I got it home all the usual stuff was missing from a computer that was "disposed of"; the hard drive, memory chips and graphics card, and so I stuck some parts in it I had laying around to see if it worked or not and when I tried it out the computer refused to start up, when I pushed the alien head shaped power button the computer did absolutely nothing, it wouldn't light up or anything.

I thought maybe it was a bad power supply so I stuck a known good power supply in that I had laying around and tried to power it up, still no dice, so I stuck the original power supply back into the computer.

I looked over the motherboard and there were no bulging caps or anything that I could see and there didn't appear to be any lightning damage either.

Does anyone here have any experience with these Alienware Desktop Computers and what could cause them not to power on?

Any help with this would be appreciated.

Never had any of that make. Make sure the parts you added are listed as compatible on the manual for your model and seated properly.

OK, the memory it uses according to the manual is DDR4 and I had some DDR4 memory chips laying around but possibly it might of been the wrong speed of DDR4 memory, because I know at one time (during the DIMM and SODIMM era anyways it used to matter what speed of memory you used on certain motherboard makes and models.)

Also maybe the wrong videocard?

I'm not familiar with high end gaming computers and how they spec out and or how they work compared to a normal non-gaming computer.

I would guess that gaming computers would use differently spec'd parts compared to a non-gaming computer and maybe that was my problem?

Normally, gamming computers have more big cabinets, robust PSU, better ventilation and a motherboard with a lot of slots, for using 2 videocards + soundcard etc, and accepts hi-end CPU, due to choosen chipset. Most are prepared to accept the lowest end RAM for compatibilities (is not needed to test with hi-spec RAM), but sometimes yes, incompatibilities can occur.

There's also error correcting RAM VS non-error correcting IIRC.

You either have a dead power supply, perhaps the one you tried was not compatible, or the motherboard has a problem. The fact you aren't even getting the POST screen rules out memory, disk drive, etc. I've had an alienware laptop for 15 years and it still works. Huge, heavy with metal cabinet, extra cooling and so forth as has been mentioned. I would imagine the desktop versions are similar.
Bad video card would keep you from seeing the POST screen but you would still be seeing fans, lights come on and so forth.

Most likely as you said. I mentioned making sure things are connected right as I have had a couple of cases of motherboards playing dead when ram was installed in a rush and cockeyed enough to short socket pins.... I've also on a different occasion had ram modules short internally and cause playing dead. Making sure hardware works out on other gear or is new is important.

May also want to sub the CPU clock battery... Earlier this week my laptop played dead on me because the little 3V clock battery which has been dead for months somehow got worse. I think I have seen similar at some point in the past too.

Sometimes when people scrap computers, they take screws out of the hard drives, cards, etc and leave them loose in the case. And they roll around in transport and end up under the motherboard shorting things out. I would loosen the motherboard and make sure nothing is behind it.