What Is Malware and How to Remove It from Your Computer

Malware is software designed to harm a computer or steal information. It includes viruses, spyware, ransomware and adware. It can arrive through email attachments, fake downloads, infected websites or unsafe USB drives. Knowing the signs and the steps to clean an infected computer helps you act quickly.

Common types

Type	What it does
Virus	Attaches itself to files and spreads to others
Spyware	Secretly records activity or collects personal data
Ransomware	Locks or encrypts files and demands payment
Adware	Shows unwanted adverts and may redirect browsing
Trojan	Looks like a useful program but opens a backdoor

Signs of an infection

The computer is slow, overheats or fans run constantly.
Browser homepage or search engine changes without your action.
Many pop-ups or unexpected programs appear.
Files are locked, renamed or missing.
Your accounts show activity you did not start.

Step 1: Disconnect and stay calm

Disconnect the computer from Wi-Fi or the network cable if you suspect ransomware or active spreading. Do not pay any ransom or call a number shown on a screen.

Step 2: Run a full scan

Use Microsoft Defender on Windows or the built-in protection on Mac, and run a full scan. A reputable second scanner can help, but use only one active real-time protection product at a time. See how to keep Windows secure with Defender.

Step 3: Remove unknown programs and extensions

Check the installed apps list and browser extensions. Remove anything you do not recognise. Check the startup list in Task Manager, as described in how to use Task Manager.

Step 4: Change your passwords

Once the computer is clean, change passwords for email and important accounts from a different, clean device. Turn on two-factor authentication.

Step 5: Restore carefully

If the infection was serious, restoring from a backup made before the infection is often safer than trying to remove everything by hand. Check the backup for infection before restoring it.

When to get professional help

If the computer is still unstable after the steps, or if the infection affects work data, contact a qualified repair service or your company's IT team.

Frequently asked questions

Do I need to pay for antivirus software?

Built-in protection is good for most home users. Paid products add features such as identity monitoring, but they are not essential if you keep the system updated and browse carefully.

Can a phone get malware?

Yes, though it is less common on iPhones. Install apps only from official stores and keep the system updated.

Prevention is cheaper than cleaning

Most infections start with a click, a download or an unpatched system. Keep your browser and operating system up to date, avoid pirated software, and do not open attachments you did not expect. Regular backups let you recover quickly if something gets through, even when the cleaning process takes time.

Check the browser after an infection

Some malware changes the browser's search engine, homepage or proxy settings. After cleaning, reset the browser settings to defaults, check the list of extensions, and make sure the proxy setting is off unless you set it yourself. Changing your browser password and signing out of all sessions on your important accounts adds another layer of protection.