Viruses and malware are one of the most common reasons people bring their computers in for repair. The trouble is, many people don't realise their PC is infected until serious damage has already been done — whether that's stolen personal data, corrupted files, or a system that barely functions.
Here are the most common signs that your computer might be infected, and what you should do about it.
1. Your PC Is Running Unusually Slowly
A sudden drop in performance is one of the first things people notice. If your computer takes ages to start up, programs freeze regularly, or simple tasks like opening a browser feel sluggish, malware could be running in the background consuming your system's resources.
Of course, a slow PC doesn't always mean a virus — it could be a failing hard drive, insufficient RAM, or too many startup programs. But if the slowdown appeared out of nowhere, malware is worth investigating.
2. Unexpected Pop-Ups and Adverts
If you're seeing pop-up windows even when your browser is closed, or being redirected to strange websites when you search for something, adware or a browser hijacker has likely made its way onto your system. These types of malware generate revenue for attackers by forcing you to view adverts or visit specific sites.
3. Programs Opening or Closing on Their Own
If applications are launching without you clicking them, windows are opening and closing by themselves, or your cursor seems to move on its own, your computer may be under remote control. This is a serious security threat and should be addressed immediately.
4. Your Antivirus Has Been Disabled
Many types of malware are designed to disable your antivirus software as one of their first actions. If you notice that Windows Defender or your antivirus program has been turned off and you can't re-enable it, that's a strong indicator of infection.
5. Unusual Network Activity
Malware often communicates with external servers — sending your data out or receiving instructions. If your internet connection seems slower than usual, your data usage has spiked for no reason, or your router lights are constantly blinking even when you're not actively using the internet, something could be running in the background. Our Wi-Fi troubleshooting guide can help you rule out network issues first.
6. Missing or Encrypted Files
Ransomware is one of the most damaging types of malware. It encrypts your personal files — documents, photos, videos — and demands payment for their return. If you notice files have disappeared or their extensions have changed to something unfamiliar, disconnect from the internet immediately and seek professional help.
7. Emails Sent From Your Account Without Your Knowledge
If friends or contacts tell you they've received strange emails or messages from your accounts, your system or accounts may be compromised. Attackers use compromised email accounts to spread malware further or launch phishing attacks against your contacts.
What Should You Do?
If you recognise any of these signs, here's what we recommend:
- Disconnect from the internet — this stops malware from sending data out or downloading more harmful software.
- Don't enter passwords or banking details — if a keylogger is active, everything you type could be captured.
- Run a full antivirus scan — if your antivirus is still working, run a thorough scan. Windows Defender's offline scan can catch threats that a normal scan might miss.
- Back up important files — if you can still access your files, copy them to an external drive before attempting any fixes.
- Get professional help — some infections are deeply embedded and require specialist tools to remove completely. A partial cleanup can leave behind rootkits or backdoors that re-infect your system later.
How We Can Help
At PC Repair Services Edinburgh, we deal with virus and malware infections every week. Our virus and malware removal service includes a thorough deep-clean of your system, removal of all threats, and installation of proper protection to help prevent future infections.
We also offer a full data recovery service if your files have been affected, and can set up a fresh Windows installation if the infection is too severe to clean.
Whether you bring your PC to us, or we come to you with our home callout service, we'll get your computer back to full health. Book a repair online or give us a call.