Computer viruses, browser hijackers and fake pop-ups can be confusing and stressful, especially when your laptop suddenly starts behaving strangely. One day everything is working fine, and the next your browser is opening random pages, your homepage has changed, your computer feels slow, or you are seeing warnings you do not recognise.
At Geeks Callout London, we regularly help home users and small businesses deal with infected Windows PCs, laptops and browsers. In many cases, the problem starts from a suspicious download, a fake update, a spam email attachment, an infected USB stick or a browser extension that the user did not realise was unsafe.
This guide explains, in plain English, how to check your computer, remove common infections and reduce the chances of the same problem happening again.
How Do You Know If Your Computer Has a Virus?
Not every slow computer has a virus, but there are some warning signs you should not ignore.
Your computer may be infected if:
Google Chrome, Edge or Firefox keeps opening strange pages
Your browser homepage or search engine has changed by itself
You see pop-ups claiming your computer is infected
Your PC is much slower than usual
Unknown programs have appeared on your desktop
Your antivirus keeps showing warnings
Emails are being sent from your account without your knowledge
Your computer freezes, crashes or restarts unexpectedly
You are being asked to call a number to “fix” your computer
A website or pop-up is demanding payment or ransom
Many customers contact us because their browser has been hijacked. This is very common and does not always mean your whole computer is destroyed, but it does need cleaning properly.
First Step: Stay Calm and Do Not Click Random Warnings
If a pop-up says “your computer is infected” and asks you to call a number, download a tool or pay money, do not rush.
Many of these warnings are fake. They are designed to scare you into giving remote access or payment details. Microsoft, your bank, HMRC or any government department will not suddenly lock your browser and ask for payment through a random pop-up.
If you see something suspicious:
Do not call the number on the screen
Do not enter card details
Do not give remote access to anyone you do not know
Do not install extra software from the pop-up
Close the browser if possible
Restart the computer if it is stuck
Once you have stopped interacting with the warning, you can start checking the machine properly.
Step 1: Run a Trusted Malware Scanner
A good first step is to run a trusted malware scanner. One commonly used tool for adware and browser hijackers is AdwCleaner by Malwarebytes.
This type of tool can help remove unwanted browser extensions, adware, toolbars, suspicious settings and programs that may be causing redirects or pop-ups.
Basic process:
Download AdwCleaner from the official
Malwarebytes website.Save it to your desktop or downloads folder.
Open the program.
Accept the terms.
Click Scan Now.
Review the results.
Quarantine or remove the detected items.
Restart your computer when asked.
This can be very useful if Chrome, Edge or Firefox has been hijacked, or if your browser keeps opening advertising pages by itself.
Important: always download security tools from the official website. Do not download antivirus or “PC cleaner” tools from random pop-ups, adverts or unknown websites.
Step 2: Remove Suspicious Browser Extensions
Browser extensions are a common cause of unwanted pop-ups and search redirects. Some extensions look harmless but quietly change your search engine, track browsing behaviour or push adverts.
Check your browser extensions and remove anything you do not recognise.
In Google Chrome:
Open Chrome.
Click the three dots in
the top-right corner.
Go to Extensions.
Open Manage Extensions.
Remove anything suspicious or unknown.
In Microsoft Edge:
Open Edge.
Click the three dots in the top-right corner.
Go to Extensions.
Choose Manage extensions.
Remove anything you do not trust.
After removing suspicious extensions, restart the browser and check whether your homepage and search engine are back to normal.
Step 3: Delete Temporary Files
Temporary files can build up over time and sometimes hold unwanted files left behind by installers, browser activity or old system processes. Cleaning them will not remove every virus, but it is a useful part of a proper clean-up.
On a Windows PC:
Click Start.
Search for Disk Cleanup.
Open the tool.
Select your main drive, usually C:.
Click Clean up system files.
Tick the boxes for temporary files and other safe clean-up options.
Click OK.
This can also free up disk space and help your computer run a little better. It is a safe maintenance step and can be done every few months.
Step 4: Run a Full Antivirus Scan
After removing obvious adware or browser hijackers, run a full antivirus scan using a trusted antivirus program. This could be Microsoft Defender, Malwarebytes, McAfee, Norton, Bitdefender or another reputable security product.
The important thing is to use a recognised antivirus, keep it updated and run a full scan rather than only a quick scan.
A full scan may take longer, but it checks more areas of the system, including files, programs, downloads and hidden locations where malware may sit.
At Geeks Callout London, we do not recommend installing lots of antivirus programs at the same time. This can slow your computer down and sometimes cause conflicts. Use one reliable antivirus and keep it properly updated.
Step 5: Check Installed Programs
Sometimes unwanted software is installed like a normal program. It may appear as a toolbar, cleaner, updater, search assistant or free utility.
To check installed programs on Windows:
Click Start.
Go to Settings.
Open Apps.
Check the list of installed apps.
Uninstall anything suspicious, unknown or recently installed without your permission.
Be careful not to remove important drivers or software you genuinely use. If you are unsure, ask a professional before uninstalling system-related programs.
Step 6: Change Your Passwords After Cleaning
If your computer has been infected, especially if you noticed strange browser activity, email issues or scam pop-ups, it is sensible to change important passwords after the machine has been cleaned.
Start with:
Email account
Online banking
Microsoft account
Google account
Facebook and social media
Shopping accounts such as Amazon or eBay
Business accounts and cloud storage
Do not change passwords before cleaning the computer, because if malware is still active, your new password may also be exposed.
Use strong, unique passwords and enable two-factor authentication where possible.
Step 7: Update Windows and Your Browser
Outdated software can make your computer easier to attack. Security updates are not just annoying pop-ups; many of them fix weaknesses that viruses and hackers try to exploit.
Make sure you update:
Windows
Google Chrome,
Microsoft Edge or Firefox
Microsoft Office
Adobe software if installed
Antivirus software
Important drivers where needed
Keeping software updated is one of the simplest ways to reduce future infection risk.
How to Protect Your Computer from Viruses
Once your computer is clean, the next step is prevention. Most infections happen because of one careless click, a fake download, an unsafe email attachment or remote access given to the wrong person.
Follow these simple habits:
Use a trusted antivirus and keep it updated
Do not install unknown “PC cleaner” tools
Do not give remote access to strangers
Never trust pop-ups claiming to be Microsoft support
Do not open suspicious email attachments
Be careful with links in text messages, WhatsApp and emails
Check the website address before logging into banking or payment sites
Avoid downloading cracked software, fake updates or illegal programs
Do not plug unknown USB sticks into your computer
Keep Windows and your browser updated
Back up your important files regularly
A good backup is very important. If your computer is ever badly infected, damaged or locked by ransomware, having a recent backup can save your files.
A Note About Fake Microsoft and Bank Scams
Many London customers contact us after seeing a warning on the screen saying their computer is infected and they must call a number. In many cases, this is not a real virus warning. It is a scam page designed to frighten the user.
The scammer may ask you to install remote access software, then show you normal Windows logs and pretend they are serious errors. They may then ask for payment to “fix” the computer.
Remember:
Microsoft will not randomly call you to say your computer has a virus.
Your bank will not ask you to move money because of a pop-up.
HMRC or the police will not lock your browser and demand payment.
If this has happened to you, disconnect from the internet, do not make any payments, and get the computer checked.
When Should You Call a Professional?
You may be able to remove simple adware yourself, but some problems need professional attention.
Call a computer repair specialist if:
The virus keeps coming back
Your browser is still hijacked after cleaning
You cannot open antivirus software
Your files are missing or encrypted
Your computer is very slow after infection
You gave remote access to someone suspicious
You entered banking details after seeing a warning
Your business computer or work files are affected
You are not sure what is safe to remove
It is better to get help early than risk losing data or making the infection worse.
Geeks Callout London Virus Removal Support
At Geeks Callout London, we help customers remove viruses, malware, browser hijackers, scam pop-ups and unwanted programs from laptops and desktop computers.
We can also help with:
Windows clean-up
Browser repair
Antivirus setup
Data backup
Slow computer repair
Business PC security checks
Our aim is not just to remove the infection, but to explain what happened and how to reduce the chance of it happening again.
If your computer is acting strangely, opening unwanted pages or showing fake warnings, do not ignore it. Get it checked before it causes a bigger problem.
Author 's Profile
Aamir.M
Aamir Mehmood is a Senior IT Consultant & Technology Writer with over 15+ years of experience and one of the founders of Geeks Callout, an award-winning London-based IT support company specialising in PC, MacBook, and gaming repairs. He is recognised for delivering reliable, customer-focused IT solutions. Under his leadership, Geeks Callout has won multiple honours, including the 2023 Business Excellence Award and the 2025 SME UK Enterprise Award. Aamir also writes insightful articles to simplify complex technology, making him a trusted voice in London’s IT community.
