Howdy fellow Reddit'ers. Hope this message finds you well.

I will cut straight to the chase because I think this post will be pretty big already.

So I have encountered this hardware issue I can't seem to fix and since I am running out of ideas I decided to resort to Reddit.

Late in the 25th of December afternoon (think of a christmas gift), computer suddenly shut down, and when turning back on, it was stuck on an infinite restart loop, and obviously stuck on Windows repair also. Soon it wouldn't even turn on anymore (after like 2 attempts to get out of the loop through manually restarting it), with just fans spinning. Bit of a background story, I had blue screens randomly over the last couple of months from time to time (symptom of a dying psu), and also had an overheat shutdown hours prior to the fatal shutdown. Figured it might be relevant information.

My first thought was motherboard is fried, and acquired a compatible motherboard days later, also acquired 4 GB DDR3 RAM for it. Hell even a new cooler just to make sure the overheat issue is fixed down the line. Problem persisted so I thought psu, got a new one and problem remains. At last, got a second hand working processor and just when I thought it would boot, nah. So basically I have almost two computers in hands. (can return all components with money back so don't worry, safe investment and went for it as I wanted to resolve the issue quick).

Note this problem used to happen in the past every time I would clean the PC Tower but a simple CMOS reset used to work all the time. Not anymore. Mouse obviously is ON with the computer and GPU fans but no signal anywhere, not on the keyboard nor even a beep. Nothing on monitor, and it isn't the issue as I tried it with other computer and it worked.

Attempted: ✔ I am pretty sure (like 200% positive as I got some knowledge myself) that everything is connected and tight where it needs to be including the 4 PIN CPU connector and of course the 24 PIN that powers the mobo. ✔ With or without graphic cards (using integrated graphics) still no boot. ✔ CMOS battery reset doesn't work at all. ✔ Only switching the processor didn't work (putting new one on old motherboard). ✔ Switching PSU didn't work. ✔ Tried all the RAM "tricks" (cleaning contacts, trying without one stick, etc..). ✔ Switching motherboards didn't work either. ✔ Didn't even try old PSU on new components as I didn't want to risk frying another motherboard due to a defective supply unit. (So at this point, almost a new computer is set up - a brand new RAM stick, motherboard, PSU and second hand working processor put together don't boot at all, only fans spinning and nothing else). ✔ Hell I even tried switching cables maybe the power cable was defective. False. ✔ Plugging off any power source and holding the power button for almost a minute to discharge energy did not work. ✔ Condensors seem fine and on the old motherboard even the green light is on (I could be wrong but the new one doesn't seem to have one or my eyes are failing me big time (or it is Dead on Arrival lol) ✔ Connecting the power cable to any other wall plug didn't work either, hell, at this idea-less point the plug could be defective lol. ✔ Checked with a multimeter, PSU is fine.

Unless DOA, I refuse to believe a brand new RAM stick doesn't work or a motherboard has broken integrated graphics or that otherwise working CPUs have suddenly broke down at the same time. EDIT: A third, compatible, CPU doesn't boot it either so...

In any case all the fans spin (and even a green light is ON on one of the motherboards but no boot.)

I have absolutely no idea anymore and so I resort to the Reddit community for enlightenment.

What I have:

Motherboards: ASUS P5KPL-CM AsRock G41C-GS r2.0

Processors: (LGA 775 socket) Intel Dual Core E5200 2.5 GHZ Intel Dual Core E6300 2.8 GHZ

4 GB DDR3 1333 MHZ stick. 2x 2 GB DDR2 (No idea about frequency but compatible with the Asus mobo)

Two PSUs, one of them brand new.

Samsung SATA 2 HDD, working (works on another computer)

Gigabyte Radeon R7 240, 100% working (and 2 other compatible cards which I haven't used in a while but yeah not the issue). (Well integrated graphics don't boot either so..)

Any feedback would be appreciated immensely. Sorry for the extension of the post!