You know your computer has malware if you notice slow performance, frequent crashes, excessive pop-up ads, unexpected browser redirects, new toolbars, disabled security tools (like antivirus or Task Manager), missing files, strange error messages, or unauthorized account activity, all indicating background processes or malicious changes. To confirm, run a full scan with your antivirus software like Windows Defender to detect and remove threats.
These symptoms could be a sign that your device is infected with malware.
Symptoms of Malware
How to remove malware from a PC
Run A Virus Check Using Windows Defender (Win 10)
If you suspect that your system has a malware infection, the first thing you should do is run a virus scan. If the scan identifies malware, follow these malware removal steps: Use a free malware removal tool: There are several free malware removal tools available online.
While a factory reset does a good job of removing most malware and viruses, it is not 100% effective. That's because some sophisticated threats called rootkits and bootkits can infect your motherboard and the startup process.
Running a malware scanner should be enough to get rid of most standard infections. If you already have an antivirus program on your device, you should download an on-demand malware scanner different than the one you are using for antivirus.
Symptoms of a viral infection depend on where you're infected, but some common ones include:
Covers crucial steps: identifying malware symptoms, quarantining systems, disabling System Restore in Windows, remediation, scheduling scans and updates, re-enabling System Restore with restore points, and user education.
Signs that your computer running Windows might be affected by a virus or malware
Run Anti-Malware Software
Make sure you're using the most up-to-date version of the software so you're better protected from current threats. If its scan detects an infection, follow the anti-malware program's prompts to remove the offending code.
The most common symptoms of a computer virus infection are…
Your computer slows down without any reason. Your computer system has less available memory than it should. Unknown programs or files are being created. Programs or files become missing.
To remove a virus, disconnect from the internet, boot into Safe Mode, and run a full antivirus scan. You may also need to delete temporary files, uninstall suspicious programs, and use specialized virus removal tools like Malwarebytes if needed.
Steps to Run a Full Scan using Windows Defender
Click on the shield icon, which is labeled as Windows Security. Click on Virus & threat protection. Select Scan options. Click on Full scan, then press the Scan now button.
Signs and symptoms of an infection
But antibiotics only treat infections caused by bacteria. They don't work on viruses. The good news is that viral infections usually aren't serious. Most will go away in a few days without medical treatment.
If it's a viral illness, typically symptoms are shorter lasting and classically the symptoms include fever, chills, sore throat, nasal congestion, runny nose, cough, and a lot of times you can have some body aches.
How to get rid of a virus on your computer: Step-by-Step
Some advanced forms of malware can cause permanent damage to your PC, such as hardware damage, locking you out, or data loss. However, if you use a good antivirus and regularly scan Windows for errors, you can keep your system running smoothly.
How to remove a virus from a laptop or a PC
The best antivirus software for 2026 consistently includes Norton 360, praised for its comprehensive features (VPN, password manager, cloud backup) and strong lab results, and Bitdefender, noted for excellent threat protection, low system impact, and user-friendliness, with options like McAfee offering unlimited device coverage and free choices like Microsoft Defender (built-in) or Malwarebytes being popular for specific needs. Your choice depends on budget and needed features, with Norton and Bitdefender often leading overall, while free options or those for Macs (like Intego) are also highly rated.
Essentially, the interactions between apps are restricted, making it hard for a virus to spread from application to application.