Symptoms
- Freshly assembled PC shows no display and possibly no beeps
- Fans spin but nothing progresses past that
- This is the very first power-on attempt after building
- Some cables or components may not have been double-checked
Likely causes
- CommonRAM not fully seatedThis is the single most common first-boot issue on new builds.
- CommonCPU power cable (4/8-pin) not connected, only the 24-pinIt's easy to forget the separate CPU power connector near the top of the board.
- CommonFront panel power switch cable connected to the wrong pinsA tiny connector wired backward or to the wrong pins prevents powering on properly.
- CommonGraphics card not seated or not poweredNew builds with a dedicated GPU need both correctly done.
- PossibleCPU not fully seated or a bent pin (on socket types with motherboard pins)Less common but a serious issue if it occurred during installation.
What to do
- Recheck that both the 24-pin and CPU power (4/8-pin) connectors are fully seated into the motherboard.
- Reseat the RAM sticks, making sure they click in on both sides in the correct slots per the manual.
- Reseat the graphics card and confirm its power cables are connected if it needs them.
- Double-check the front panel power switch connector against the motherboard manual's pinout diagram.
- Confirm the monitor is connected to the graphics card (if installed) rather than the motherboard.
- Try a minimal boot: CPU, one RAM stick, and the monitor connected directly to onboard graphics if available, removing the GPU temporarily to isolate it.
- Check for a case standoff installed under a spot without a mounting hole, which can short the motherboard.
Tools and parts
- Motherboard manual
- Anti-static precautions
When to call a pro
If a methodical minimal-boot test still doesn't POST, a PC builder or repair shop can test each component individually to find the faulty or misconfigured part.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.