How Do I Run a Virus Scan?

Author : pallavi singh | Published On : 11 Aug 2026

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Running a virus scan is one of the easiest ways to check your computer for malware, viruses, spyware, and other potentially harmful software. If your computer is running slowly, showing unusual pop-ups, crashing unexpectedly, or behaving differently than normal, a virus scan can help determine whether a security threat is responsible.

If you are asking, “How do I run a virus scan?”, the process is generally simple. You can use the built-in security tools included with your operating system or a reputable antivirus program. Most security applications provide several scanning options, including quick scans, full scans, and more advanced scans for persistent threats.

This guide explains how to prepare your computer, start a virus scan, choose the right type of scan, understand the results, remove detected threats, and improve your computer's security after scanning.

What Is a Virus Scan?

A virus scan is a security check that examines files, programs, memory, system locations, and other areas of your computer for known or suspicious threats.

Modern security software can detect many different types of malicious or unwanted software, including:

Computer viruses
Trojans
Spyware
Ransomware
Worms
Adware
Keyloggers
Potentially unwanted applications

The exact items checked depend on the security software and scan type you choose.

A scan does not guarantee that every possible security problem will be discovered. However, regularly using reputable security software can help identify many common threats.

Why Should You Run a Virus Scan?

You should consider running a virus scan when your computer behaves unexpectedly or as part of regular security maintenance.

Common reasons include:

Your computer suddenly becomes slow.
You see unusual pop-ups.
Your browser redirects to unfamiliar websites.
Unknown applications appear.
Your security settings change unexpectedly.
Programs crash frequently.
You notice unusual network activity.
You opened a suspicious attachment or downloaded an unfamiliar file.
You want to perform a routine security check.

Even if your computer appears normal, occasional security scans can provide an additional layer of protection.

How Do I Run a Virus Scan?

The exact instructions vary depending on your operating system and security software. The following process applies broadly to Windows computers and reputable antivirus applications.

Step 1: Save Your Work

Before beginning a detailed scan, save documents and close unnecessary applications.

A full scan can use system resources, which may make your computer temporarily slower.

Saving your work also prevents the loss of unsaved information if the security software or operating system requires a restart.

Step 2: Update Your Security Software

Before running a scan, make sure your antivirus or security software is up to date.

Security programs regularly receive updates containing information about newly discovered threats. Running an outdated scanner may reduce its ability to identify newer malware.

If you use Windows, open Windows Security and make sure the application's security intelligence and Windows updates are current.

If you use a third-party antivirus product, update it through the provider's official application.

Avoid downloading antivirus updates from unknown websites.

Step 3: Open Your Security Application

Launch the security software installed on your computer.

On Windows, you can search for Windows Security from the Start menu.

Once the application opens, locate the section related to virus and threat protection.

If you use another reputable antivirus product, look for its main dashboard or scanning section.

Step 4: Select the Scan Option

Most antivirus programs provide multiple scanning options.

Common choices include:

Quick Scan
Full Scan
Custom Scan
Offline Scan

The names can vary between security products.

Select the scan that best matches your needs.

What Is a Quick Virus Scan?

A quick scan examines common locations where malware is likely to be found.

It generally takes less time than a full scan and is useful for routine checks or when you need to perform an initial security check.

A quick scan may examine active processes, commonly targeted folders, startup locations, and other important areas.

However, a quick scan does not necessarily examine every file on your computer.

If you suspect a serious infection, follow it with a full scan.

What Is a Full Virus Scan?

A full scan checks substantially more files and locations across your computer.

Because it examines more data, it can take significantly longer than a quick scan.

The duration depends on factors such as:

Number of files
Storage capacity
Computer performance
Type of storage drive
Security software
Number of running applications

During a full scan, your computer may feel slower than usual. This is normal because the security software is using system resources to inspect files.

For a thorough security check, a full scan is generally the better choice.

How to Run a Virus Scan With Windows Security

Windows includes built-in security features that can scan for many types of malware.

To run a scan:

Open the Start menu.
Search for Windows Security.
Open the application.
Select Virus & threat protection.
Look for the scanning options.
Choose Quick scan, Full scan, or another available scan.
Start the scan.
Allow it to finish.
Review the results.

The exact appearance of Windows Security may differ depending on your Windows version and installed security configuration.

If a threat is detected, follow the recommended action shown by Windows Security.

How to Run a Virus Scan With Antivirus Software

If you use a reputable third-party antivirus program, the process is usually similar.

Open the antivirus application and look for options such as Scan, Security Scan, or Virus Scan.

Choose the desired scan type and start the process.

Do not install several unknown antivirus programs simply because you want additional protection. Multiple security applications with overlapping real-time protection can sometimes interfere with one another.

Use a trusted security product and keep it updated.

What Should You Do During a Virus Scan?

Once the scan begins, allow it to complete.

Avoid opening suspicious files or websites while the scan is running.

You can continue using your computer for basic tasks if the security software allows it, but intensive activities may make the scan take longer.

If the antivirus program asks you to restart the computer, save your work and follow the instructions.

Do not manually stop the security process unless there is a good reason to do so.

How to Understand Virus Scan Results

After the scan finishes, the security software will normally display a summary.

The result may indicate:

No threats found
Threats detected
Threats quarantined
Threats removed
Potentially unwanted applications detected
Items requiring further action

If no threats are found, that is a positive result, but it does not mean that your computer can never have security problems.

If threats are detected, carefully review the information provided by your security software.

What Should You Do If a Virus Is Found?

If your antivirus software detects a threat, follow its recommended security action.

Depending on the application, you may see options such as:

Quarantine
Remove
Delete
Block
Repair

Quarantine isolates the suspicious item so it cannot operate normally.

Do not manually delete unfamiliar system files. Some legitimate files may look suspicious if you do not recognize their names.

Allow trusted security software to determine whether a file is malicious.

After removing or quarantining a threat, restart your computer if recommended and run another scan.

What Is an Offline Virus Scan?

Some malware can be difficult to detect while the operating system is running.

For persistent or serious security concerns, an offline scan can be useful.

Windows Security includes an offline scanning feature that can restart the computer and perform a scan outside the normal Windows environment.

Before starting an offline scan:

Save your work.
Close your applications.
Make sure important files are backed up.
Start the offline scan through Windows Security.
Allow the computer to restart.
Wait for the scan to finish.

The computer may restart automatically during the process.

How Often Should You Run a Virus Scan?

There is no single schedule that works for everyone.

Your antivirus software should provide real-time protection continuously if that feature is enabled.

In addition, you can perform periodic manual scans.

A quick scan can be useful as a routine check, while a full scan can be performed when you suspect a problem or want a more comprehensive examination.

The most important security habit is not simply running scans frequently. It is keeping your operating system, browser, applications, and security software updated and avoiding suspicious downloads and links.

What If the Scan Finds Nothing but Problems Continue?

Sometimes a computer may behave strangely even when a virus scan reports no threats.

Possible causes include:

Too many startup applications
Insufficient storage
Outdated drivers
Browser extensions
Hardware problems
Overheating
Corrupted system files
Outdated applications
Network problems

If problems continue, investigate these possibilities instead of repeatedly installing different antivirus programs.

You can also run another scan using a reputable security tool if appropriate.

Check Your Browser After a Scan

If your main problem involves pop-ups, redirects, or unwanted search results, inspect your browser after completing the virus scan.

Check your installed extensions and remove anything unfamiliar.

Also review:

Homepage settings
Search engine settings
Notification permissions
Startup pages
Site permissions

If unwanted behavior continues, consider using the browser's official reset or restore-settings feature.

Protect Your Computer After Running a Virus Scan

Running a virus scan is only one part of computer security.

After completing the scan, follow good security practices.

Keep Your Software Updated

Install operating-system, browser, and application updates from legitimate sources.

Updates often contain security fixes.

Download Software Carefully

Only download applications from reputable sources.

Avoid pirated software, suspicious installers, and programs advertised through questionable pop-ups.

Be Careful With Email Attachments

Do not open unexpected attachments simply because they appear to come from someone you know.

If an attachment seems unusual, verify it with the sender before opening it.

Use Strong Passwords

Use unique passwords for important accounts.

A password manager can help create and store strong passwords.

Enable Two-Factor Authentication

Two-factor authentication adds another layer of protection to accounts that support it.

Maintain Backups

Regularly back up important documents, photos, and other files.

A backup can be especially valuable if your computer is affected by ransomware or another serious security incident.

Final Thoughts

If you are asking “How do I run a virus scan?”, start by updating your operating system and security software. Then open your trusted antivirus application, choose an appropriate scan such as Quick Scan or Full Scan, and allow the process to complete.

A quick scan is useful for an initial check, while a full scan provides a more comprehensive examination of your computer. If persistent problems continue, an offline scan may provide an additional way to investigate difficult-to-detect threats.

If the scan identifies malware, follow the security software's recommended instructions to quarantine or remove it. Avoid manually deleting unfamiliar system files or installing suspicious programs that claim to provide instant virus removal.

Finally, remember that good computer security involves more than running occasional scans. Keep your software updated, download applications carefully, avoid suspicious links and attachments, use strong passwords, enable two-factor authentication, and maintain reliable backups.

These practices can help you detect potential threats earlier and keep your computer safer over time.