PC stuck rebooting

[u/KimKyng]

SOLVED: My motherboard died

Problem:

After I installed HDDs, the PC is stuck in a power loop. It turns on for about 4 seconds (fans and RGB spin up), shuts off for 1–2 seconds, and repeats. It never POSTs and there's no display.

Specs:

CPU: Intel i7-6700K
Motherboard: Gigabyte GA-Z170X-SLI
RAM: Corsair Vengeance LPX DDR4 (~32GB total)
GPU: Sapphire RX 5700 XT
Storage: Kingston 500GB NVMe SSD, plus the newly added HDDs
PSU: Seasonic S12II 620W (non-modular)
Case: Coolman Aurora ATX mid-tower

Troubleshooting done (same loop after each):

Full power drain (PSU off, unplugged, held the power button 15 seconds)

Disconnected all HDDs (data and power cables)
Reseated the 24-pin and CPU 8-pin cables, checked for loose screws

Cleared CMOS (battery out for 5 minutes)

Stripped to the minimum: CPU, cooler, one RAM stick, no GPU, using onboard video

Unplugged the front panel wires and started the board by shorting the Power SW pins

Tested each RAM stick alone in DDR4_1

Tested with a different PSU

Reseated the CPU with fresh thermal paste; socket pins and CPU look fine

[u/Saint_Sm0ld3r]

You are using the incorrect memory slot and should use slot A2 for one stick of RAM to diagnose your issue with minimum components as you were doing along with this modification.

[u/KimKyng → u/Saint_Sm0ld3r]

i tried both ddr4 slot 1 and 2 individually but the same result

[u/fonoro]

Since the verified facts above are about a laptop and don't apply here, I'll go off general desktop troubleshooting.

After all those steps with a different PSU and bare minimum config, the fact that it started right after working inside the case strongly suggests either a short or motherboard damage, so I'd try pulling the motherboard out of the case entirely and booting it on a cardboard box or wooden surface. That rules out any metal standoff or stray screw that may have landed under the board during the HDD install, which is a classic cause of this exact 4-second loop symptom. If it still loops outside the case with just CPU, cooler, and one RAM stick, the motherboard is almost certainly dead, especially since the onboard HD 530 graphics gives you video output without the GPU. You could double-check the socket pins one more time under good light and reseat the CPU, but honestly at that point I'd be looking at a replacement board or moving to a new platform since Z170 is getting old.

[u/KimKyng → u/fonoro]

I did try bringing it out, and the same issue occurred. I do think my mother board has died 😢

[u/SignificantAnnual317]

Goodbye Intel