My PC won’t turn on — what to check first

My PC Won’t Turn On — What to Check First

Before you panic, there’s a good chance it’s something simple. Work through these checks in order — many people find their computer is fixed before they reach the end.

Before you start

This guide covers desktop PCs and laptops that appear completely dead — no lights, no sounds, no fan, nothing happens when you press the power button. If your computer turns on but won’t load Windows, that’s a different problem — see our guide: What does the Windows Blue Screen of Death mean?

Take your time with each step. Many “dead” computers are brought back to life with a simple fix that takes less than five minutes.

Step 1: Check the obvious things first

It sounds too simple, but these are the most common causes and they’re always worth ruling out first:

For desktop PCs:

• Is the power cable fully plugged into the back of the PC and the wall socket?
• Is the wall socket switched on? Try plugging something else in to test it
• Is the extension lead or surge protector switched on? Has it tripped?
• Is the switch on the back of the PC (if there is one) set to the on position? It should be set to I, not O

For laptops:

• Is the charger properly plugged into the laptop and the wall?
• Is the charging LED lit? If not, try a different wall socket
• Try removing the charger and battery (if removable), hold the power button for 30 seconds, reinsert the battery, plug in the charger, and try again
• Try a different charger if you have access to one — charger faults are very common

Step 2: Listen and look for any signs of life

Press the power button and pay close attention:

• Do any lights flash, even briefly? A brief flash suggests the PC is getting power but something else is preventing it from starting
• Do you hear the fan spin up for a second before stopping? This often points to a RAM or graphics card issue
• Do you hear any beeping sounds? Different beep patterns indicate different hardware faults — note how many beeps and whether they’re short or long
• Can you feel the fan moving at all through the vents?

Any of these signs mean the machine is getting power, which rules out the most basic problems and narrows things down considerably.

Step 3: Try a different power socket and cable

Power cables develop faults more often than people realise. If you have another kettle-lead style cable (the kind most desktop PCs use), swap it out and try again. Same with laptop chargers.

Also try a completely different wall socket — not just a different socket on the same extension lead, but a different circuit entirely if possible. Extension leads with surge protection can silently trip and stop supplying power.

Step 4: Disconnect everything that isn’t essential

External devices can occasionally prevent a PC from starting — particularly if a USB device is confusing the startup process.

Unplug all of the following:

• USB drives and memory sticks
• External hard drives
• Printers and scanners
• Monitors (except one)
• Docking stations or USB hubs
• Any external speakers or webcams

Leave only the keyboard, mouse, and one monitor connected, then try the power button again.

Step 5: Check your monitor (desktop PCs)

A common scenario: your PC is actually on and working fine, but the monitor isn’t displaying anything — making it look like the computer is dead.

• Is the monitor powered on? Check its own power light
• Is the cable from the PC to the monitor secure at both ends?
• Try pressing the monitor’s input button to cycle through sources (HDMI, DisplayPort, VGA)
• Try a different cable or a different monitor if you have one

If the PC’s power light is on and you can hear the fans running but see nothing on screen, this is almost certainly a monitor or cable issue rather than a PC fault.

Step 6: Try a hard reset

Sometimes a PC gets stuck in a state where it won’t start normally. A hard reset can clear this:

1. Hold the power button for 10 full seconds until everything shuts off completely
2. Unplug the power cable from the wall
3. Wait 60 seconds — this clears the residual charge from the components
4. Plug back in and press the power button

For laptops with a removable battery: remove the battery as well as the charger during the 60-second wait.

Step 7: Check for a CMOS battery issue (desktop PCs)

Every desktop PC has a small coin-sized battery on the motherboard (called the CMOS battery) that keeps the clock and basic settings when the PC is unplugged. If this battery dies — typically after 5–10 years — the PC can refuse to start or behave erratically.

Signs this might be the problem:

• The PC is several years old
• The clock resets to the wrong date every time you start it
• You see a message about BIOS settings when it does occasionally start

CMOS batteries (CR2032) cost around £2–3 and are easy to replace. However, if you’re not confident opening up a PC, this is something we can sort quickly at Computer Repair Bolton.

Step 8: Reseat the RAM (if you’re comfortable opening the PC)

This step involves opening your PC case, so only attempt it if you’re comfortable doing so. If not, skip to the section below.

RAM (memory sticks) can work loose over time due to vibration and temperature changes. When this happens, the PC often won’t start at all.

1. Shut down and unplug the PC completely
2. Open the side panel (usually one or two screws at the back)
3. Find the RAM — long, thin sticks plugged into slots near the processor
4. Press the clips at each end to release them, pull the RAM out carefully
5. Reinsert firmly until you hear a click at both ends
6. Close up, reconnect, and try again

⚠️ Always unplug from the mains before opening any computer. Touch a metal part of the case before handling components to discharge static electricity.

When to stop and call a professional

If you’ve worked through all the steps above and the PC still won’t start, the fault is likely one of the following — all of which require professional diagnosis:

• Failed power supply unit (PSU) — the component that converts mains power for the PC’s components. Very common on older machines
• Motherboard fault — less common but possible, especially after a power surge
• Failed processor — rare but possible
• Serious water or physical damage

These faults require specialist equipment to diagnose properly. Attempting them yourself risks making things worse or damaging other components.

Worried about your data?

If your PC won’t start, your files are almost certainly still intact — in most cases, a failed power supply or motherboard doesn’t affect the hard drive at all. Data recovery is usually possible even from machines that won’t start.

That said — please don’t keep trying to force a machine to start if you suspect water damage or hear grinding or clicking sounds from inside. This could cause further damage to the hard drive.

Get it sorted in Bolton

Dave at Computer Repair Bolton offers free diagnostics on machines that won’t start. In most cases we can tell you exactly what’s wrong within the hour.

Book a free diagnostic →

Or if you’d like to describe the problem first: get in touch →

Quick reference summary

Symptom	Most likely cause
Completely dead, no lights at all	Power cable, socket, or PSU
Brief flash then nothing	RAM, graphics card, or PSU
Fan spins for a second then stops	RAM issue or overheating protection
Beeping sounds on startup	Hardware fault (note the beep pattern)
Power light on but no display	Monitor, cable, or graphics card
Starts sometimes but not others	CMOS battery or loose connection
Worked after a storm or power cut	Power surge damage to PSU or motherboard

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