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Hi everyone, my fiance's computer at the moment is having some problems. Its a custom built computer thats she has had for 4 year now. And since then she's had no problems with it. Well today we wake up and turn on her computer and for no reason it turns back off by itself after a few seconds. In the beginning it looks like its about to turn on but then out of no where it will shut its self off. And if I try to turn it back on again with the power button it just turns off even quicker. But if I let it sit a bit it start powering up longer and then just dies agian. I can't even get into the windows picture on the monitor, nor see it even start loading on the Monitor. All the fans spin fine, we blew out all the dust from it and that didn't work. I'm thinking it may be the Power supply or the mother board. What do you guys think?

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As and pointed toward power and cooling as likely areas, the behaviour described — powering up then dying within seconds, with no video — is almost always a hardware failure rather than an OS problem. Common causes to consider beyond obvious fan/dust checks are a failing power supply (PSU) that collapses under load, motherboard shorts or damaged voltage-regulator circuitry (VRMs), leaking/bulging capacitors, or a faulty front‑panel/power-switch wiring.

A practical isolation path: with mains unplugged, reduce the system to a minimal configuration (PSU, CPU+cooler, one RAM stick, and video). Power that minimal setup and observe whether the board stays on; if it does, add components back one at a time to find the culprit. If it still dies immediately, the fault is likely PSU or motherboard VRMs. PSU diagnosis can be done either by trying a known-good unit or by measuring the 20/24-pin connector rails with a multimeter while the PSU is supplying the board. Expected approximate ATX tolerances: +12V ≈ 11.4–12.6V, +5V ≈ 4.75–5.25V, +3.3V ≈ 3.14–3.47V; rails that collapse when connected indicate PSU failure.

A careful visual inspection often reveals motherboard problems: look for bulging or leaking electrolytic capacitors, scorch marks, or evidence of a short to the case (bad standoffs). Front-panel switch faults can mimic PSU issues; removing the power-switch header and momentarily shorting the two power pins on the motherboard reproduces the button press for testing. POST beep codes or on‑board diagnostic LEDs (and adding a basic motherboard speaker if needed) give valuable clues. Also verify that the CPU heatsink is properly seated and thermal interface is present, since some boards will shut down quickly on thermal protection.

Opening or repairing a PSU is hazardous because internal capacitors retain charge; such work should be left to qualified technicians. If tests point to the PSU, replacement is the safest option. Significant motherboard damage (bulging caps, burnt traces) generally requires board replacement. Noting exact symptoms, any beep codes or LEDs, and whether a known-good PSU restores stable power will decisively narrow the fault.

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Member Avatar for cguan_77

borrow a power supply from a friend..clean the dust on the processor fan.. check if it will help

Member Avatar for c-tech

same advice as above here. Try blowing off the dust in the CPU and check if all the fans are moving freely. looks like overheating due to dust or fan failure.

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