How to Fix Virus & Malware Infection — Windows & Mac Removal Guide

To remove a virus or malware infection, disconnect the computer from the internet, run a full offline scan with your antivirus, then remove anything you don't recognise from installed programs, startup items and browser extensions. Change your important passwords from a different, clean device. If files are locked behind a ransom note, or the infection keeps returning, a clean reinstall is the only dependable fix.

The order matters more than the tools. Many people make an infection worse in the first ten minutes by typing passwords into the affected machine, calling the number on a fake warning, or installing five "cleaner" programs at once. The steps below protect your files and accounts first, and clean the computer second.

How can you tell it is malware and not just a slow computer?

Slowness on its own proves very little. A tired hard drive, low memory or a long list of startup programs will slow a PC down without any malware involved. Malware tends to show up as a pattern: behaviour you didn't cause, settings you didn't change, or software you never installed. This table links common signs to likely causes.

What should you do in the first ten minutes?

Containment comes before cleaning. The goal is to stop the infection talking to the internet, stop it spreading to other drives, and stop you handing over more passwords. Do these in order, and don't skip ahead to scanning until the first three are done.

1. Cut the connection. Turn off WiFi and unplug any Ethernet cable. This stops data leaving the machine and stops ransomware reaching shared folders.
2. Stop typing credentials. No banking, email or work logins on this computer until it is clean.
3. Remove external drives. Unplug pen drives and backup disks so they don't pick up the infection or get encrypted.
4. Ignore the phone number. Pop-ups that display a support number are scams. Real antivirus software never asks you to phone anyone.
5. Power down only if files are changing. If you can see files being renamed in real time, hold the power button. That limits ransomware damage.
6. Write down what happened. Note which file or website you opened just before the symptoms began. It helps with the cleanup and with any bank or police complaint.

How do you clean a Windows PC step by step?

Windows 11 already includes Microsoft Defender, and it is good enough for the first pass. The trick is to use its offline scanner, which runs before Windows loads, so malware that hides while the system is running has nowhere to go.

1. Reconnect briefly, with nothing sensitive open, only to update the antivirus definitions. Then disconnect again.
2. Open Windows Security, choose Virus & threat protection, then Scan options, and pick the Microsoft Defender Antivirus (offline scan). The PC restarts and scans.
3. Afterwards run a full scan, not a quick scan.
4. For a second opinion, run an on-demand scanner from a reputable security vendor, downloaded from the vendor's own site. A second scanner is fine. Two real-time antivirus programs fighting each other is not.
5. Open Settings, Apps, Installed apps and sort by install date. Uninstall anything you don't recognise from around the time the problems began.
6. Open Task Manager, go to Startup apps and disable unfamiliar entries. Check the browser for unknown extensions and review which sites may send notifications.
7. Check Settings, Network & internet, Proxy. A proxy you never configured is a classic sign of a hijack.
8. Restart, rescan, and watch the machine for a day or two.

What should you avoid doing?

Don't install a pile of "PC cleaners" or registry optimisers, because many are the problem rather than the cure. Avoid cracked "removal tools" from torrent sites, which are a common way infections arrive in the first place. And never delete files inside the Windows or System32 folders by hand, however confident a forum post sounds. You can turn a recoverable infection into an unbootable PC in one click.

Is a Mac different, and what do you check there?

Macs include Gatekeeper, notarisation checks and XProtect, so classic viruses are rare. What Macs actually catch is adware, bundled unwanted apps, fake update prompts and hijacked browser extensions, often arriving with pirated software. The cleanup is manual and quick if you know where to look.

• Open Activity Monitor and look for unfamiliar processes using lots of CPU.
• Check System Settings, General, Login Items & Extensions, and remove anything you didn't install.
• Look in System Settings, Privacy & Security, Profiles. A configuration profile you didn't add can force a homepage or proxy on you. It only appears if profiles exist.
• Review extensions in Safari and Chrome and remove the unknown ones.
• Drag unrecognised apps from the Applications folder to the Bin, empty it, and install pending macOS updates.

If the behaviour persists, back up your documents, erase the Mac and reinstall macOS. Our price list shows a macOS reinstall with data migration at ₹1,499 to ₹2,999, indicative.

When is a clean reinstall the right answer?

Reinstalling feels drastic, but sometimes it is the only way to be sure. Consider it if the same threat returns after every scan, if antivirus can't update or start, if system files are damaged, or if a banking trojan or keylogger was involved. In those cases you can never fully prove the old system is clean.

Copy only your documents, photos and similar data, scan them on a clean device, and leave programs and system folders behind. Reinstall software from official sources. Our guide on resetting versus repairing Windows explains the options, and our backup guide shows how to keep a safe copy first. If you'd rather hand it over, advanced malware removal is listed from ₹599 to ₹1,299 for laptops and all-in-one PCs, indicative, after a ₹350 inspection that is refunded if you proceed. See laptop virus removal or virus removal for the service details.

What if ransomware has encrypted your files?

Disconnect, photograph the ransom note, and don't pay. Payment doesn't guarantee a working key, and it marks you as a paying target. Don't wipe the drive yet: free decryptors for some ransomware families appear later, and the No More Ransom project, backed by law enforcement and security companies, lists the ones that exist. An up-to-date backup is the real cure. For details on this threat see ransomware removal.

Which passwords and accounts should you secure afterwards?

Use a different, clean device for this. Start with your main email account, because it can reset every other password. Then change banking, shopping, cloud storage and work logins, and turn on two-step verification using an authenticator app rather than SMS where possible. Sign out of all other sessions in your Google, Microsoft and Apple accounts. If you typed card or net-banking details on the infected machine, tell your bank promptly. In India, financial fraud can be reported on the national helpline 1930 and at cybercrime.gov.in.

How do you avoid catching it again?

• Skip cracked Windows, Office and games. They are one of the most common infection routes.
• Use a standard user account for daily work and keep the administrator login for installs.
• Keep Windows, browsers and drivers updated.
• Treat unexpected attachments and "your parcel is held" links as hostile until proven otherwise.
• Keep at least one backup that is disconnected from the computer. Our notes on antivirus software for Windows 11 cover what extra protection is worth paying for.

Frequently asked questions

Can malware survive a reinstall of Windows?

Almost never. Reinstalling from fresh Windows media wipes the system partition, which removes ordinary malware, rootkits included. Firmware-level infections exist but are rare. The bigger risk is restoring an infected backup, so scan your documents before copying them back and don't restore programs.

Is free antivirus enough?

For most home users, Microsoft Defender in Windows 11 is a reasonable baseline when it stays updated. Your habits matter more than the brand: no cracked software, careful with attachments, regular updates. Paid suites add extras but are optional rather than essential.

Do Macs need antivirus?

Not usually, because of the built-in protections. Adware, fake installers and malicious browser extensions still happen, so keep macOS updated, install apps only from the App Store or trusted developers, and review login items if the Mac starts acting strangely.

How much does professional malware removal cost?

Our price list shows advanced malware removal from ₹599 to ₹1,299 on laptops and all-in-one PCs, indicative. The final quote depends on the infection and whether a reinstall is needed. You get a written quote before any work begins.

If you'd rather not gamble your accounts and files on trial and error, book a free doorstep pickup and we'll inspect the machine and quote in writing before touching anything. You can also check indicative rates on our pricing page.