This is a very common problem, and most of the time it’s easily fixed.
“is it plugged in” ASSUMPTIONS: (what people usually miss)
- MB power + [4/8] CPU power
- GPU additional power (if req.),
- The display is plugged into the correct GPU/port (not MB if 3rd party GPU exists
- CPU seated correctly
- PSU switch “ON”
- Power SW on right pins
- RAM is FIRMLY into place and it’s on the Motherboards’ QVL “Approved” list (important if it’s very fast ram)
Once you’ve verified all is plugged in correctly (Which solves 90% of problems) continue on now:
- Do a real quick paper-clip test on your psu.
- Pull the ram, power cycle it, put it back in. try it.
- Loosen the screws on the motherboard that mount it to the case, and move it a bit. try it.
- Take it all apart, and build it out of the case. (This is called bread-boarding it) No optical/HDD/SSD – Use onboard video instead of GPU if applicable) try it.
- If no change, take all sticks of ram out then try it (it should do a certain number of beeps – if you have a case speaker, plug it into the motherboard if not, no worries, you will not hear beeps just continue. The put back in the ram then try it and try it. If no change, take out the video card. try it.
- If no change, unplug and take out everything (except the CPU+fan and power switch, unless you can use a screwdriver to touch the two pins of the power switch, that’ll turn it on just like pushing the power button) , then take out the bios battery, and unplug the PSU from the WALL, then try it (yes I know there is no power, but the fans may move a little while the power is dispensed) then try it. Wait at least 30 seconds after you hit power to put the bios battery back in.
- Take out the CPU, (check for bent pins) then try it. (should hear beeps) If no change, Put back in the CPU+GPU+ram and try it. If no change, try any variation you can think of. (Forget the HDD/SSD/Optical, those won’t make it not boot).
- Sure enough, unless there is something legitimately wrong, you will get working again. If nothing works, you probably do indeed have a bad motherboard. Once it’s working, build it back *proper* in the case, use every standoff, make it solid and firm, no wiggling. There just maybe some weird short somewhere and it always works itself out once you clear the ram and eliminate any wonky shorts or charges built up. Once it gets up and running out of the case, you’ll be good.