How to know if your computer has a virus? This post will show you some common warning signs of malware infection on computers. Meanwhile, it will introduce you two ways in Windows to verify it and you can also detect computer for virus with third-party antivirus programs. You can browse the details from this post offered by MiniTool.

Sometimes, you may wonder “do I have a virus”, there is a scenario you may not like, but it can happen to you every day. Imagine you’re working on an important project, and all of a sudden, there are annoying pop-ups showing up on your computer, or it takes too long to load files or applications, and now you need to check if your computer is infected with malware. 

At this point, your computer may have been compromised by a virus or the next generation of malware that is slowing down its performance. This is one of many warning signs that your computer may be infected with malware and there are many things you need to pay attention to and understand, so you can act quickly. 

Tip: There are some popular types of computer virus you should know. Click to get details.

Signs of Infection

Not all viruses are similar, and some affect computer systems differently than others. Thus, how to tell if your computer has a virus? 

In most cases, there are several visible warning signs to keep an eye on, like sluggish performance, odd pop-up dialog boxes, unexpected crashes, disabled antivirus tools, a different browser homepage, or a slow internet connection.

In some situations, a PC virus won’t cause any noticeable changes to your system. In this case, consistent scanning with a quality antivirus program is the only way to protect your computer. 

Knowing what symptoms to look out for is handy, but software and hardware issues often cause similar problems, hence it’s highly recommended to run multiple scans with different antivirus programs. 

Tip: According to some researches, some Windows utilities are used by malware. If you are interested in this topic, you can click to get more information.

Sign 1: Your Computer Is Slowing Down

How to know if your computer has a virus? If apps on your computer run slowly and it takes a longer time to start than usual, it seems that your computer has a virus. As you know, one of the main activities of malware is to slow down the operating system, whether you are browsing the Internet or just accessing a local application. 

Tip: There are other reasons why your computer is slow. Read this post to get more information: 10 Reasons for Computer Lagging and How to Fix Slow PC.

Sign 2: Annoying Ads Are Displayed

How to know if you have malware? If you always receive annoying ads which can be opened randomly, or get strange messages, this is a sign of a malware infection and your computer will be severely damaged. 

It might be spyware, which is used to secretly collect and steal your personal information without your permission. 

In this case, the main problem is not only that your Internet browsing will be affected by a large number of pop-up windows, but it is also very tough to remove spyware from your system. These pop-up windows are always bundled with other hidden malware threats, making them even more damaging to your operating system. 

In order to collect your passwords and other personal information, they can be disguised as legitimate programs, and then they can monitor your web browsing data and online activities. Thus, it is strongly recommended that you never click on a suspicious pop-up window. 

Tip: If annoying ads are not caused by malware, you can remove them: How Do I Remove Ads From Windows 10 – Ultimate Guide.

Sign 3: Crashes

You are just playing games or watching videos online, but your laptop keeps crashing. The screen will freeze, and then you get Blue Screen of Death. Then your laptop recovers and tells you that your computer has been recovered from the shutdown. 

In this case, you should be careful because this could be a malware issue. 

Tip: If your hard drive crashes on Windows, you can read this post to get methods to recover data.

Sign 4: Pop-up Messages

How to know if your computer has a virus? If you keep getting the warning message “You’re running out of disk space on Windows (C:)”, generally, this means that the partition C is running out of free space on your computer. 

However, it might be another sign of malware infection. Many types of malicious programs can use various ways to fill all the available space on your hard drive, which will crash your hard drive.

Sign 5: Internet Traffic Increases

If you find the Internet traffic suspiciously increases on your computer every time you start it, it seems that your computer has a virus. 

If there is no program or application that’s downloading any data, no update for a certain app running at this moment or no large download that may still be running in the background, and you still don’t know what makes Internet traffic increase, it is possibly a malware issue.

Sign 6: Your Browser Homepage Changed Without Your Knowledge

If your browser homepage changes without your input, or a new toolbar pops up, or you’re redirected to a different URL, these are signs of malware infection. 

This could be because you accidentally clicked on a link or pop-up window on the site. This will trigger the unnecessary software download and installation on your device. These effects are malicious, which can damage your data.

Sign 7: Unusual Messages Show Unexpectedly

If you get warning messages that appear unexpectedly, it could be a technical issue, but it also may be a malware issue. 

There are some warning signs you need to be careful about. If your programs open and close automatically, the OS of your Windows shuts down unexpectedly, or you are informed that you lose access to your drives, it may be the malware that takes over your computer and slows down it.

Check If Your Computer Has a Virus

Check Computer for Virus with Windows Task Manager

If you’re not ready to use antivirus software to scan your computer, it is a good place to start for you to check for unusual or strange processes with Windows Task Manager.

Some malware runs when you boot your computer and tries to disguise it as a typical Windows process. You can do a quick search on Google to see if a process is legit or what needs further research. 

Step 1: Press Win + X keys together and then click Windows PowerShell (Admin) to run it.

Step 2: Type the command shutdown /r /t 0, and then press Enter.

Step 3: When your computer restarts, right-click the taskbar and select Task Manager.

Step 4: Right-click a suspect process and then choose Search online.

choose Search online to check the process information

Your default browser will bring up Bing search results. Read through multiple search results to ensure that process information is consistent.

Scan Computer for Virus with Windows Defender

Windows Defender is an anti-malware application built into the operating system. Running on Windows 8 and 10, Windows Defender Antivirus is a worthwhile tool if you think your computer is infected. 

Step 1: Type windows defender settings in the search bar and then choose Windows Defender settings to open it.

Step 2: Click Open Windows Defender Security Center.

Step 3: Choose Virus & threat protection and then click Advanced scan.

Step 4: Choose a scanning option – Full scan/Custom scan/Windows Defender Offline scan and then click Scan now.

click Scan now to scan for virus

After finishing scanning virus, all potential threats will be listed. 

Tip: If your Windows Defender is not turning on, get methods from this post to fix this issue.

Check Computer for Virus with Third-Party Antivirus Programs

While Windows provides its own virus and malware protection tool, it’s always a good idea to scan your system with various antivirus software. That’s because every program has its own database of virus signatures. 

In some cases, Windows may not flag files, but other antivirus tools do. Using multiple antivirus software from different software vendors to scan your computer is the best way to get accurate information on what is going on.

I always wonder “do I have a virus”. After reading this post, I can detect malware infection on my computer with ease.Click to Tweet


A Powerful Tool to Keep Your Data Safe

In many cases, if your computer is infected with a virus, the data on your computer will be lost. Therefore, in order to keep your data safe, you need to back up your data in advance. You are highly recommended to use great backup software – MiniTool ShadowMaker. 

MiniTool ShadowMaker is a powerful data protection and disaster recovery tool for your PC. With it, you can back up files, partitions, Windows operating system, and disks. Besides, you can also clone the whole hard disk. You are also allowed to restore data if you encounter system crash, hard drive failure, and more. 

Meanwhile, if your computer can’t boot successfully, you can create bootable media (CD/DVD disc, USB flash drive or USB hard drive) to restore your OS to the previous normal state. 

MiniTool ShadowMaker is also a powerful piece of file sync software, by using the Sync function of it, you can synchronize files and folders to other locations to keep your data safe, too. 

Right now, you can download and install MiniTool ShadowMaker Trial Edition to back up your data to keep your data safe.

MiniTool ShadowMaker TrialClick to Download100%Clean & Safe

The following part will show you how to make a data backup with the Backup function of MiniTool ShadowMaker. 

Step 1: Choose the Source File

1.Run MiniTool ShadowMaker to enter its interface.

2.Click Connect in the Local module to continue.

3.After entering the main interface of MiniTool ShadowMaker, click the Backup tab to continue.

click the Backup feature to continue

Tip: In general, the system reserved partition and C drive are selected by default. You can choose another backup source – file/folder/disk/partition which you want to back up.

4.Click the Source module firstly and then select the source type you want to back up. Here, you should choose files as backup source to avoid losing data.

 select the source file

Step 2: Choose a Destination Path to Save Backup Files

1.Click the Destination module.

2.Then click a destination where you want to save backup files. There are 5 types of destination paths for you to choose – Administrator, Libraries, Computer, Network and Shared. Click OK to continue.

select a destination path

Step 3: Perform Backup Operation

1.Click Back up Now to execute the backup operation immediately. You can also choose Back up Later to carry out the operation later, and you need to click Back up Now in the Manage page to execute the pending operation.

perform backup operation immediately

Tip: MiniTool ShadowMaker provides some advanced backup settings to meet your different needs. They are backup options, schedule setting and backup scheme.

You can make some advanced settings for each new backup task during the process of backup, such as adding a comment, compressing files, etc. It can also help you automatically back up PC daily, weekly, monthly, and on event and manage disk space usage by deleting the specified backup image file versions.

2.Read the confirmation and click Yes to continue. You can also check Shut down the computer when all the running backup tasks are finished.

confirm to start backup operation now

Tip: If you are interested in the Scheme function, read this post –  3 Types of Backup: Full, Incremental, Differential – MiniTool.

In addition to the Backup function, Sync is also a powerful feature of MiniTool ShadowMaker to keep your data safe. With this function, you can sync files and folders. The following part will show you how to sync files with this feature. 

Step 1: Run MiniTool ShadowMaker to enter its interface. 

Step 2: Select the files you want to sync from the Source tab. 

Step 3: Select a destination where you want to save the synced files from the Destination tab.

select the sync destination

Step 4: Click Sync Now to perform this operation immediately. You can also choose Sync Later to execute synchronization operation later, and you need to click Sync Now in the Manage page to carry out the pending operation. 

Tip: MiniTool ShadowMaker also provides you with some advanced synchronization settings like the Backup function. They are synchronization options and schedule setting. You can make some advanced settings for each new task during the process of synchronization – compressing files, and setting exclude conditions to filter synced files. 

It can also help you automatically sync files daily, weekly, monthly, and on event. 

After you complete all the steps above, you can successfully sync files to keep them safe. 


How to know if your computer has a virus? You can refer to the signs of virus or malware infection above. If your computer has one of these signs, you need to pay attention to your computer and take action quickly. 

If you have any problems when you are using our program, please contact us via the email [email protected].

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