Member Avatar for akalsha

Hello,
My mother has an Compaq Presario that's a few years old. It's running Windows XP Pro. She called and said that the peripherals started working intermittently (monitor, keyboard, mouse), and now they don't work at all. She says that the PC turns on, but nothing else does. No lights on the keyboard, monitor doesn't come on.....

Does anyone know what the problem could be? I'm going to go over and try to fix it. I've done basic work on PC's like adding memory, drives... so I'm pretty comfortable "getting under the hood".
Thanks for any help.

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Dani AI

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A short, practical checklist to narrow down where the fault lies (complements 's direction without swapping parts blindly). Focus on quick verification, safe PSU checks, and visible motherboard clues that are often missed on older Compaq Presario systems.

  • Try the monitor/keyboard/mouse on a known-good PC to rule out external gear. Confirm the monitor's own power LED and try a different VGA/DVI cable.
  • Note keyboard type: PS/2 keyboards get power during POST and will usually show LEDs only if the board is powering the controller; USB keyboards sometimes stay dark until drivers load. Testing both types helps separate board vs OS/device behavior.
  • Inspect the motherboard visually: look for bulging or leaking electrolytic capacitors around the VRMs and near the CPU/PSU connectors. A burnt smell or scorch marks is a strong indicator of board failure.
  • Make sure the internal speaker is connected for beep codes; many systems are silent without it. Try reseating RAM and testing a single stick in the primary slot.
  • Reset CMOS by removing the CR2032 battery for a few minutes and then replacing it.

If comfortable with basic mains safety, a PSU bench check narrows things quickly:

  • Disconnect the PSU from the motherboard and drives, then start the PSU by shorting PS_ON (green wire on the ATX connector) to any ground (black) with an insulated tool. Measure the main rails on a Molex connector with a multimeter (+3.3V, +5V, +12V) and check that 5VSB is present even before PS_ON is shorted.
  • If 5VSB is absent, the PSU or its standby circuitry is likely dead. If 5VSB is present but the system will not start or show POST/beeps, the motherboard or front-panel/header circuitry is suspect.

Cautions: avoid live probing if unsure, use ESD protection, and remember some Presario models used proprietary connectors—confirm compatibility before swapping PSUs.

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Member Avatar for willcomp

First impression is a failed motherboard or faulty power supply.

Disconnect/remove everything but motherboard, CPU, memory, power supply, monitor and keyboard. If it still won't boot replace any components you can starting with power supply.

Let us know if there are any beeps on boot and whether the PC turns on at all (e.g. fans run, lights flash).

Member Avatar for akalsha

Thanks, I will try that and get back to you.

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