How to Fix a Computer That Won’t Turn On (Complete Troubleshooting Guide)

Device

When a computer will not power on, the issue is usually related to power delivery, hardware failure, or a simple connection problem. Follow the steps below in order, from easiest to most advanced and save yourself a trip to the computer shop. These are literally the steps we take when performing a diagnostic.

1. Check External Power First

Power connections to check during dianostics — Power connections to check during diagnostics

Make sure the power cable is firmly plugged into the wall and the computer.
Try a different wall outlet or power strip.
If using a laptop, test with and without the battery installed.
Look for indicator lights on the power adapter or laptop body.

2. Inspect the Power Button

Various styles of Power Buttons on Modern Computers.

Press and hold the power button for 10–15 seconds.
Check for a stuck or damaged button.
On desktops, ensure the case power button cable is connected to the motherboard.

3. Remove All External Devices

Unplugging USB Devices to Eliminate Potential Conlicts — Unplugging USB Devices to Eliminate Potential Conflicts

Disconnect:

USB devices
External drives
Printers
Monitors (temporarily)

A faulty peripheral can prevent startup.

4. Check for Signs of Life

Inside a Typical Desktop Computer, fans are spinning in this Scenario

Look for:

Spinning fans
Beep codes
LED lights
Clicking or buzzing sounds

No signs at all usually indicate a power supply or motherboard issue.

5. Power Supply Test (Desktop PCs)

A typiclal Desktop Power Supply, this one has a Power Switch (PSU Switch) — A typical Desktop Power Supply, this one has a Power Switch (PSU Switch)

Ensure the PSU switch is set to ON
Reseat the 24-pin motherboard power connector
Reseat the CPU power connector (4-pin or 8-pin)
If possible, test with a known-working power supply

6. Reseat Internal Components

RAM and GPU being Re-Seated to esure proper contact. — RAM and GPU being re-seated to ensure proper contact.

Turn off and unplug the computer, then:

Remove and reseat RAM (test one stick at a time)
Reseat the graphics card
Disconnect and reconnect storage drives

Loose components are a common cause of no power.

7. Clear the CMOS / BIOS

A CMOS Battery on a Motherboard Most Batteries are CR2032 Cells.

Remove the CMOS battery for 5 minutes
Or use the motherboard’s clear CMOS jumper
Reinstall the battery and try again

This resets corrupted BIOS settings.

8. Test Minimal Hardware Setup

An ATX Style Motherboard Outside the Case with CPU Removed.

Boot with only:

Motherboard
CPU + cooler
One RAM stick
Power supply

If it powers on, add components back one at a time.

9. Check for Motherboard or CPU Failure

Swallen Capacitors on a Motherboard — Swollen Capacitors on a Motherboard will cause failure,

Look for:

Burn marks
Bulging capacitors
Bent CPU pins

If found, replacement is usually required.

10. Laptop-Specific Checks

Power Jack pushed in and Bent to One side.

Inspect the charging port for looseness
Try a different compatible charger
Perform a hard reset (remove battery + hold power button 30 seconds)

11. When to Seek Professional Repair

If the system still won’t turn on after all steps:

The motherboard, CPU, or power circuitry may be dead
Professional diagnostics or replacement is recommended

Final Notes

Most “won’t turn on” issues are caused by power supplies, loose connections, or faulty RAM. Always start with simple checks before replacing hardware. Following this guide step by step helps isolate the failure accurately and safely.