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How to remove malware and adware from a Windows PC using safe scanning and cleanup steps

Malware and adware are annoying and can slow your PC, steal data, or show unwanted ads. This guide walks you through a calm, step-by-step cleanup using safe scanning and removal methods so you can restore performance and privacy. Follow each step methodically and keep backups if possible.

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  1. Step 1: Back up important files

    Copy your important documents, photos, and work files to an external drive or cloud storage before you start. A 1–2 GB sample backup proves the process works; full backups avoid data loss if you need to restore later.

    [Illustration: external hard drive with folders being copied on a Windows desktop screen]

  2. Step 2: Disconnect from the network

    Unplug Ethernet or turn off Wi-Fi to isolate the PC and stop malware from communicating outward. Staying offline prevents additional downloads or data exfiltration while you scan, then reconnect only when directed.

    [Illustration: PC showing network icon being toggled off with a disconnected cable nearby]

  3. Step 3: Reboot into Safe Mode

    Restart the computer and press Shift+Restart, then choose Troubleshoot > Advanced options > Startup Settings and pick Safe Mode with Networking if needed. Safe Mode loads minimal drivers, reducing active malware and improving scan effectiveness.

    [Illustration: Windows Advanced Startup Options screen with Safe Mode selected]

  4. Step 4: Run built-in Windows Defender scan

    Open Windows Security and run a Full scan (not Quick) which checks all files and running processes; allow at least 1–2 hours depending on disk size. Defender can remove many common threats and is a good first layer of defense.

    [Illustration: Windows Security app showing a Full scan progress bar on a laptop screen]

  5. Step 5: Use a second-opinion scanner

    Download and run a reputable on-demand scanner like Malwarebytes Free or another respected tool; perform a full system scan and quarantine anything it finds. A second opinion catches items the first scanner missed; scans typically take 30–90 minutes.

    [Illustration: Third-party anti-malware app scanning list of detected items on a Windows desktop]

  6. Step 6: Clean browser adware and extensions

    Open each browser, reset settings to default, and remove unknown extensions or plugins; clear cache and cookies for the last 7–30 days. Many adware infections manifest as unwanted toolbars or redirects that a reset and extension removal will fix.

    [Illustration: Browser settings page with extensions list and reset options highlighted]

  7. Step 7: Install updates and restore network

    Reboot normally, reconnect to the network, then install Windows updates and update all security software immediately; restart again if requested. Keeping the OS and software current closes vulnerabilities that allowed the infection.

    [Illustration: Install updates and restore network]


  • Keep a current backup schedule, like weekly full backups or daily critical-file backups to an external drive.
  • Create a system restore point before major changes so you can roll back in 1–2 steps if needed.
  • Use strong, unique passwords and enable two-factor authentication on key accounts after cleanup.
  • Limit admin accounts: run daily tasks from a standard user account and use admin only for installs.
  • If a scanner quarantines files, review quarantine list before permanent deletion to avoid removing needed system files; keep quarantined items for 7–14 days.
  • Consider creating a rescue USB with reputable antivirus rescue media to disinfect an unbootable system.

  • Do not download or run random removal tools from unknown websites; they can add more malware.
  • Avoid paying ransom or following instructions from ransomware notes — contact a professional and isolate the PC instead.
  • If financial or personal data may be exposed, change passwords from a clean device and monitor accounts for 30–90 days.
  • If the system shows persistent rootkit signs, data theft, or you cannot remove the infection after two different reputable scanners, seek professional malware removal assistance.

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