There’s usually a four prong power connector on the top left corner of the motherboard. I always forget that one, nothing works without it plugged in too.

Just jumping in here to let you know that most of the people here missed one of the most basic and first steps in pc repair… CLEAR THE CMOS!!!

There might be a jumper on the mb but the easy way is to remove the battery and try to turn the power on and off a few times.

Replace the battery and the computer should try to POST.

I know it seems crazy but sometimes computers that won’t post had major hardware changes and the bios won’t let power through. Not sure why but clearing the cmos will revert to defaults and get you to the next step of troubleshooting.

Source: 20 years pc repair technician.

Here are the steps I would take. Powering the device on each time it seems logical and see if anything has changed.

-Check the power switch on the power supply. -Make sure the power cable is seated into the power supply. -Listen for any unusual noises when power supply is on -Open the computer and look for any codes or lights on the mobo, Google it -Check RAM is properly seated -Check all of the power cables visible to me from opening the case. 8-pin at the top, 24-pin on the right side, any hard drives/ssds, cable for graphics card -Inspect computer for any hot spots -Unplug video cable from graphics card the into the one on the mobo, this only works with some newish AMD, but most Intel processors are going to have onboard graphics -If nothing comes up and I can’t see any problems, you will have to start taking things out of the computer -Start with removing the graphics card -Check for any sort of damage to the power port and PCIe on the card and the slot Removing the card should allow better visibility of the mobo -Remove the back panel (if you need to) to see if all of the power supply cables are properly seated -Check any cable management in the back or any hard drives/ssd mounted back there

After this, if nothing has changed and I don’t have any more info I would probably take apart completely, check for any kind of damage, put back together and test again with the bare minimum and adding stuff as I go. If you don’t know how to take apart or put a computer together I would follow a guide on YT.

After that you should def have an idea what isn’t working, if everything looks fine it can be the power supply If the power supply seems okay and mobo isn’t showing any kind of lights or code (or signs of life) that is your best candidate

As you add stuff it should give you the best indication and if you are unsure, post another edit

My best guess based on your post is a dead motherboard but going through the steps like you want will avoid having to purchase an expensive thing for no reason

First thing. If you stick your hand in the case, make sure the powercord is disconnected from the power supply, and then press the powerbutton. This discharges capacitors.

Don’t fret too mich, it’s like Lego, most stuff only first one way, and you don’t need much force to plug or remove stuff. If you need to use more force than you can apply with your finger, mostly you are missing a latch, hook or something else that is holding the thing in place… check again.

The machine has an onboard Videocard. So a good option is to remove the Videocard and test the system to see if it gives any sign of life without the graphics card.

Removing the graphics is a bit tricky as it usually has a little latch near the back of the connector it is in on the motherboard (check a quick YouTube video on removing a graphics card).

Then try if it starts.

Then check all the connectors if they are seated properly. Especially all the small cables in the motherboard, they listen really carefully and must be on the correct headers.

Check if it starts again.

Remove and re-seat the internal memory. I’d recommend quick YouTube video here too. It only fits one way.

Check start again.

Then disconnect all other devices like the harddisk etc. just pull the cable on the drive side and leave it dangling… it’s only for testing.

Of none of this works, I’d recommend getting the guy that traded it help you out.

The motherboard has an onboard battery that could have been empty and by having it plugged in it charged a little. I’d check if the system just works now.

Make sure the RAM is seated correctly. If the tabs on the sides of the modules are not fully locked, the module is not seated. This will cause the system not to boot.

Depending on what cpu it is, you should be able to try it without the gpu. Also Google the mobo and try to find its manual. The manual will tell you things like what you can plug in and where. It’ll tell you compatibility crap too. You’ll have two spots on the back where you plug in the displayport/hdmi cable for your monitor – the gpu, and the mobo. Use mobo port and take out the gpu and see if it starts. POST is key. My old gigabyte was a badass and had a led number box so troubleshooting was cake. With other ones, there’s gonna be miscellaneous spots with lil lights that’ll blink (the manual for the mobo will tell you)

Is it posting? There should be led indicators that flash, usually an array of them. (The pattern as it lights up means stuff.) and if connected to a monitor, it should also flash some kind of boot screen. If it completes posting, it’ll at least go to bios. If the LEDs aren’t flashing at all…

the first step is to pull everything out and re-seat it. (Ram, gpu, power, etc.)

Start with seating the power sockets (to mobo, the minimum needed RAM, cpu and cpu fan (connected to cpu_fam header; usually next to the cpu).

Side note on ram, if it’s dual-channel or more, it matters where the ram goes. Consult your manual.

Okay, most absolute basic troubleshoot check: is there an on/off switch on the power supply that might be off?

Is the light on the motherboard or inside the metal box for the power supply?

More of the old, old ones would not do anything if any component was not properly seated. So maybe unplug and replug everything?

And if that doesn’t work, I would start systematically removing components to see if I could get a different response from the computer.

I do think it’s a good idea to do what you did and just try it as is, since there’s actually a pretty decent chance that it just works.

However, if it doesn’t work, i would check everything as if i’m building the PC from scratch. Are the parts compatible (good old pcpartpicker is here for that), is the PSU sufficient, is everything plugged in the way the manuals say, etc

Have you checked to make sure all the cables are seated? Unplug them and plug them back in.

The power supply connect with the motherboard in more than one place. If “the wire from the power supply plugs into the motherboard” is a thing, that may be your problem.

Unplug anything that is optional (that includes disks and stuff that you have more than 1, like maybe memory sticks) and try to power the computer. If it works, replug stuff one by one.

As BigMikeInAustin said, remove everything and plug it again. I’d add to get a paint brush and clean stuff a bit in between if it’s dusty. Make sure to clean plugs and contacts, try not to clean electronic components.

Try to remove the board’s battery for a few minutes and turn the computer on again. Some times that’s enough.

Also, turn the computer on for a minute or two, turn it off, unplug everything, and touch the surfaces to see if they are hot. Try not to touch any printed circuit board.

Do the fans spin up at all?

I might be asking a dumb question here, this is the right community for that after all. But have you asked your cousin what might be wrong?