Member Avatar for sanyboi

Ok i turned my PC on earlier an it wouldnt start up. I tried a restart and instead of helping it got worse. Now whenever the power cable is connected the fans and green power LED will come on. I try to hold down the power switch but it does nothing. I have tried disconnecting the hard drives, graphics card, RAM to pinpoint the problem and none of the previous have worked. Im thinking the problem is either the PSU or the MoBo. The current PSU i have is a 250W. Can someone help?

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  • Latest Post Latest Post by jwenting

Dani AI

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This adds a concise, prioritized checklist that builds on , and without repeating forum steps already tried. The goal is to quickly isolate whether the fault is the power delivery, the motherboard/BIOS, the front-panel wiring, or a short.

  1. Front-panel / switch rule-out — disconnect the case switch header and momentarily short the two power-on pins on the motherboard with a non-conductive tool handle with a metal tip (or a small screwdriver) to see if the board responds. If it powers only when jumped, the case switch or wiring is suspect. Take ESD precautions and power down before changing headers.

  2. PSU sanity checks — swap with a known-good PSU or use a PSU tester/multimeter to verify the main rails under load. Expected ballpark ranges: +12V ~11.4–12.6V, +5V ~4.75–5.25V, +3.3V ~3.135–3.465V. Confirm the 5V standby rail is present when the system is off but mains-connected.

  3. Motherboard quick inspection — look for bulging or leaking capacitors, burn marks, or missing standoffs. If the board has onboard POST LEDs or a two-digit POST display, consult the manual for the code shown. Attach a PC speaker for beep codes if available.

  4. Minimal bench boot (safe procedure) — outside the case on an insulated surface: motherboard + PSU + CPU + one known-good RAM stick + video (if required by board) and speaker. This rules out case shorts and peripheral interference.

  5. BIOS/compatibility note — if the board accepts power but never POSTs and hardware is intact, check the motherboard CPU/support list and the BIOS version required for newer CPUs before replacing components. Do BIOS updates only with the correct file and method (manufacturer instructions).

If these steps still leave the system unresponsive, a known-good PSU swap followed by bench testing or professional diagnostics is the fastest way to decide between PSU and motherboard replacement.

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Member Avatar for Serunson

Is your monitor showing a message similar to "No signal" when it is turned on with the PC 'on'?
If it does then this would point to a problem relating to the gfx card and the monitor itself.
Otherwise what gfx card do you own, because if it is a high end gfx card, then your power supply is too small to support it. Just to check that your PC is booting correctly, remove your gfx card and plug the monitor into the VGA port on your mobo and check to see that the computer is booting normally. IF it doesn't, then it would point to a motherboard issue.

Member Avatar for sanyboi

Ok i tried* it still doesnt boot properly. The Graphics card im using at tha moment is a nvdia geforce FX5600 DVI SVGA.

Member Avatar for jwenting

This sounds like the CPU is not recognised by the motherboard, but it does detect there's a CPU there.

If it's a new CPU it likely means it's too new for the motherboard (but maybe flashing the BIOS will solve it), if it's an old machine the CPU may be damaged and need replacement (which may also mean replacing the motherboard if you can't find a CPU that fits it and is recognised by it).

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