Look for signs like slow performance, crashes, pop-ups, browser redirects, unfamiliar startup programs, disabled security software, or unusual network activity. 2. Run a full system scan using built-in antivirus tools: use Microsoft Defender on Windows or XProtect on macOS, ensuring definitions are up to date. 3. Use a dedicated malware scanner such as Malwarebytes, HitmanPro, or Emsisoft Emergency Kit by downloading from the official site, installing, updating, scanning, and removing detected threats. 4. Check startup programs and running processes via Task Manager on Windows or System Settings and Activity Monitor on macOS, disabling suspicious entries and investigating high-resource or unknown processes. 5. Review browser extensions and settings, removing unrecognized add-ons, resetting browser settings to default, and verifying homepage and search engine configurations. 6. Monitor network activity using tools like Resource Monitor, GlassWire, or Little Snitch to detect and block suspicious outgoing connections. 7. Boot into Safe Mode—by holding Shift during restart on Windows or macOS—then rerun scans to improve detection. To stay protected, keep all software updated, avoid suspicious downloads and links, use trusted websites, and perform regular scans to catch threats early. Combining built-in and third-party tools while staying vigilant ensures effective malware detection and system security.

If you suspect your computer might be infected with malware, it's important to act quickly to minimize damage and protect your data. Here’s how to check for malware effectively:

1. Look for Common Signs of Malware

Before running scans, check for symptoms that might indicate an infection:

• Slower-than-normal performance
• Frequent crashes or freezes
• Unexpected pop-ups or ads (especially outside your browser)
• Browser redirects to unfamiliar websites
• Unfamiliar programs launching at startup
• Disabled security software
• Unusual network activity (e.g., high data usage when idle)

These signs don’t always mean malware is present, but they’re a good reason to investigate further.

2. Run a Full System Scan with Antivirus Software

Most computers come with built-in security tools:

• Windows: Use Microsoft Defender Antivirus (built into Windows Security)
  • Open Settings > Update & Security > Windows Security > Virus & threat protection
  • Click “Scan options” and choose Full scan, then run it
• macOS: Use XProtect (built-in) and consider adding a trusted third-party antivirus
  • Apple’s system scans automatically, but you can use tools like Malwarebytes for deeper checks

Make sure your antivirus definitions are up to date before scanning.

3. Use a Dedicated Malware Scanner

Antivirus software may miss certain types of malware like adware or spyware. Use a second-opinion tool:

• Malwarebytes (free version available) is excellent for detecting and removing modern threats
• HitmanPro or Emsisoft Emergency Kit can be used alongside your main antivirus

Steps:

• Download from the official website (on a clean device if possible)
• Install and update the program
• Run a full system scan
• Quarantine or remove any detected threats

4. Check Startup Programs and Running Processes

Malware often hides in startup items or background processes.

• On Windows:
  • Press Ctrl Shift Esc to open Task Manager
  • Go to the Startup tab and disable suspicious entries
  • In the Processes tab, look for high CPU, memory, or disk usage from unknown apps
• On macOS:
  • Go to System Settings > General > Login Items to review startup apps
  • Use Activity Monitor (in Utilities) to check for unusual processes

If you’re unsure about a process, search its name online to verify if it’s legitimate.

5. Review Browser Extensions and Settings

Malware often targets browsers:

• Open your browser settings and go to Extensions/Add-ons
• Remove any you don’t recognize or didn’t install
• Reset your browser settings to default (available in Chrome, Firefox, Edge)
• Check your homepage and search engine settings—malware often changes these

6. Monitor Network Activity

Some malware “phones home” or steals data in the background.

• Use tools like Windows Resource Monitor or GlassWire (Windows) or Little Snitch (macOS)
• Look for unexpected connections to strange IP addresses or domains
• Block suspicious outgoing connections if possible

7. Boot into Safe Mode for a Cleaner Scan

Malware can hide by running in the background. Scanning in Safe Mode increases detection chances:

• Windows: Restart and hold Shift while clicking “Restart,” then go to Troubleshoot > Advanced Options > Startup Settings > Restart > Enable Safe Mode
• macOS: Restart and hold Shift until the login screen appears

Then run your antivirus and malware scans again.

Keep your operating system, browser, and software updated, avoid suspicious downloads and email attachments, and stick to trusted websites. Running regular scans—especially if you notice odd behavior—can catch issues early.

Basically, combine built-in tools with a trusted third-party scanner, stay alert to warning signs, and don’t skip updates. It’s not complicated, but consistent checks make a big difference.

The above is the detailed content of How to check for malware on a computer. For more information, please follow other related articles on the PHP Chinese website!