Viruses and malware are more common than ever — and they don't always announce themselves with a dramatic warning message. Often, the signs are subtle, and by the time most people realise something is wrong, the infection has already been running for days or even weeks.
Here are the five most common signs that your computer may be infected, and what you should do about it.
1. Your Computer Has Slowed Down Dramatically
If your PC or laptop has suddenly become sluggish — taking ages to start up, open programmes, or load web pages — it could be a sign that malware is running in the background, consuming your system's resources.
Of course, slow performance can also be caused by other things (a full hard drive, too many startup programmes, or simply an ageing machine), but if the slowdown was sudden and unexplained, it's worth investigating.
2. You're Seeing Unexpected Pop-Ups
Pop-up adverts appearing outside of your browser, or unusual warning messages claiming your computer is infected and urging you to call a number or download software, are classic signs of adware or scareware. Never call the number or download anything from these pop-ups — they are almost always scams.
3. Your Browser Has Changed Without Your Permission
If your homepage has changed, you're being redirected to unfamiliar websites when you search, or a new toolbar has appeared in your browser that you didn't install, you likely have a browser hijacker. These are a form of malware designed to redirect your web traffic and collect data about your browsing habits.
4. Programmes Are Opening or Closing on Their Own
If you notice applications launching or closing without you doing anything, your mouse cursor moving on its own, or files appearing or disappearing, this is a serious warning sign. In the worst cases, this could indicate remote access malware — software that allows someone else to control your computer.
5. Your Antivirus Has Been Disabled
Some sophisticated malware is specifically designed to disable your antivirus software to prevent detection. If your antivirus has turned itself off and won't turn back on, or if you're getting errors when trying to run a scan, treat this as a red flag.
What Should You Do?
If you recognise any of these signs, here's what to do:
- Don't panic — but do act quickly
- Disconnect from the internet to prevent the malware from communicating with external servers or spreading to other devices
- Don't enter any passwords or access online banking until the issue is resolved
- Run a full scan with your antivirus software if it's still working
- Get professional help if you're unsure — attempting to remove malware incorrectly can sometimes make things worse
At The IT Workshop, our Virus & Malware Removal service is available remotely or on-site across the UK. We'll thoroughly scan and clean your device, remove any threats, and advise you on how to stay protected going forward.