Computer Maintenance · Beginner level

Beginner level · Module 3: Troubleshooting Common Problems · Lesson 2 of 3

Computers That Won't Start

Diagnose power, start-up and boot problems.

In this lesson you will

  • Diagnose no-power and no-display faults
  • Use Windows recovery options

Key concepts

no powerno displayboot errorsWindows recovery

The lesson

No lights or fans: check the socket, cable, power switch and, for laptops, the charger and battery.

Power but no display: check the monitor and cable, then reseat RAM; beeps or flashing lights indicate hardware faults explained in the manufacturer's documentation.

Windows starts but fails: use Windows recovery options — Startup Repair, Safe Mode, System Restore or uninstalling a recent update.

Step by step

  1. Test the power path.
  2. Check display connections.
  3. Reseat RAM.
  4. Use recovery options on a lab machine.
Troubleshooting tree

The computer won't start: where to look

A path from 'nothing happens' to the most likely cause.

Do any lights or fans come on when you press the power button?
  • Yes
    Does anything appear on the screen?
    • Yes
      The hardware starts, so the fault is in start-up: use Windows recovery (Startup Repair, Safe Mode, System Restore). Back up data first if the drive may be failing.
    • No
      Check the monitor, its cable and input; then reseat the RAM. Note any beep or light pattern and look it up in the manufacturer's documentation.
  • No
    Does the socket work, and is the cable (or laptop charger) known to be good?
    • Yes
      Suspect the power supply, laptop battery or power button. Test with a known-good power supply or charger; never open a power supply.
    • No
      Fix the power source: use a working socket, cable or charger and try again.

Notes

Ask what changed just before the fault — a power cut, a dropped laptop, an update — and test the simplest causes first.

Practice activity

Diagnose the no-start lab faults.

Expected result: Correct fixes for each no-start fault.

Check your understanding

  1. What should you check first when a computer shows no lights?

    Show answer

    The socket, cable and power switch.

  2. Name one Windows recovery option.

    Show answer

    Startup Repair, Safe Mode, System Restore or uninstalling an update.

Taught live by an instructor — online or in person. Free course lessons are for self-study and do not lead to a certificate — see registration options.