How to Check Your Computer for Viruses
A proper scan, using what Windows already has.
Pop-ups, a browser that has changed by itself, or a computer that has suddenly slowed can all mean something unwelcome has got in. Windows has a good scanner built in.
Step by step
- Press the Windows key, type Windows Security and open it.
- Choose Virus and threat protection.
- Choose Scan options, select Full scan, and choose Scan now. It can take an hour or more.
- If threats are found, follow the steps to remove them, then restart.
- For a stubborn infection, choose Microsoft Defender Antivirus (offline scan). The computer restarts and scans before Windows loads.
What the result means
- Nothing found, and the computer behaves: good news.
- Threats found and removed: change your important passwords from another device.
- Files are locked, or there is a ransom message: stop, disconnect from the internet, and see ransomware removal.
Not sure? Call 020 7237 6805. We are happy to talk it through, and the assessment is free.
Questions and answers
Do I need to buy antivirus software?
For most home users, the protection built into Windows is enough, if it is kept up to date.
The scan found nothing but it still misbehaves. What now?
It may be a hardware fault. See find the fault.
Is a pop-up telling me to call a number genuine?
No. That is a scam. Close the browser and do not call.
More guides
- Check your Computer Before You Call
- Check your Hard Drive or SSD
- Check your Computer’s Memory
- Check If your Computer Is Overheating
- Check your Laptop Battery and Charger
- Check your Internet and Wi-Fi
- Back Up your Files Before a Repair
Let us take a look
The assessment is free, the price is fixed before we start, and every repair carries a 3-month warranty. Call 020 7237 6805, or tell us what is wrong and a technician will reply.