Understanding How a Computer Boots

Ever wondered what happens when you press the power button on your PC or laptop? Understanding the boot process can help you recognise early signs of hardware or software problems. At Computer Repair Bolton Computers, we frequently troubleshoot slow startups, “no boot device” errors, and system failures. Here’s a simple, step-by-step explanation.

Step 1: Power Supply Activates the System

When you press the power button, the SMPS (Switched Mode Power Supply) sends electricity to the motherboard and other components.

Signs of a problem:

• PC shows no signs of life
• Fans don’t spin
• No lights on the motherboard

If this happens, the power supply or motherboard may need checking.

Step 2: BIOS/UEFI Performs a Hardware Check (POST)

The first program to run is the BIOS (Basic Input/Output System) or UEFI firmware. It conducts a POST (Power-On Self-Test) to check critical components:

• RAM (memory)
• CPU
• Graphics card
• Storage drives (SSD/HDD)
• Keyboard and essential hardware
• Warning signs:
• Beeping sounds
• Blank screen

Error messages like “No boot device found”

Step 3: Bootloader Loads the Operating System

Once hardware checks are passed, BIOS/UEFI searches for a bootable device, usually your SSD or hard drive. It loads the bootloader, which then starts your operating system (Windows or Linux).

Problem indicators:

PC stuck on spinning circle or Windows logo

Bootloader errors

Step 4: Operating System Loads

Your operating system begins loading:

• Device drivers
• System services
• Startup programs
• Causes of slow boot:
• Failing hard drive
• Too many startup programs
• Corrupted Windows installation
• Nearly full SSD

Upgrading to an SSD or cleaning unnecessary startup programs can dramatically improve boot speed.

Step 5: Desktop Appears – Ready to Use

When the desktop appears, your computer is ready for use. On modern machines, booting should take 30–60 seconds. Longer times often indicate a need for SSD upgrades, system clean-up, or hardware repair.

Common Boot Problems We Fix

At Computer Repair Bolton Computers, we specialise in diagnosing and repairing:

• PCs stuck on BIOS screen
• “No boot device found” errors
• Windows not loading
• Blue screens on startup
• Corrupted operating systems
• Failing hard drives
• Slow boot times
• Laptop startup issues

We also offer SSD upgrades to improve performance for older machines.

Areas We Cover

We provide professional computer repair services across:

• Horwich
• Astley Bridge
• Farnworth
• Smithills
• Heaton
• Little Lever
• Great Lever
• Deane

Whether you’re a home user or a small business, we deliver fast and reliable support.

Need Help With a Computer That Won’t Boot?

If your PC or laptop won’t start, don’t worry — most issues can be diagnosed and fixed quickly.

Visit us: Bolton

Call us: 07538 513916

Services we offer:

• Same-day diagnostics (where possible)
• SSD upgrades
• Windows reinstallations
• Data recovery
• Business IT support

Trust Computer Repair Bolton  for local, reliable, and professional computer repair in Bolton.