If your computer suddenly starts running much slower than usual, this could be a virus infection giveaway, since viruses can cause a computer to perform significantly worse than usual by consuming a lot of resources.

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If your computer's fan suddenly becomes unusually loud, this could be a virus warning. If this happens, the computer is being pushed to its limits by some software, possibly a virus, causing the CPU to heat up.

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Pop-ups are a common nuisance on the internet. However, if you notice a sudden increase in random pop-ups, it could indicate that your computer is infected with a virus. Some pop-up ads contain malware that, if clicked, can install itself on your computer and run without your knowledge. These pop-ups may appear as error messages, or even messages claiming your computer has a virus.

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A computer may crash or freeze when running a resource-intensive program or app. However, if it crashes or freezes frequently without any demanding programs running, it could be a sign of a virus infection.

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A browser’s homepage should not change unless the user modifies it. At most, it may open a separate tab after an update, but it won’t alter the homepage. If your browser’s homepage unexpectedly switches to a different website, your computer may be infected with a virus.

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An unknown program or app appearing on a computer could be an indicator of virus presence. A hidden virus may be launching programs that the user did not download.

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As we’ve learned, viruses consume a lot of resources, and a computer’s battery is no exception. When a computer’s battery life quickly drops, this could mean a virus is running in the background and spreading to affect the system.

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Missing or corrupted files can also indicate a virus infection on a computer. Heuristic viruses often target files, causing them to disappear or become unreadable. This not only disrupts the workflow but also poses a significant threat to personal and professional information, such as important documents, cherished photos, or critical work files.

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Computer viruses not only make files disappear but also create files and folders to disguise their presence. Some viruses modify files on a computer by giving them almost identical names, allowing them to blend in with the rest of the documents.

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Antivirus programs and security tools are some of our best allies against computer viruses. That’s why, when a virus infects a computer, it often disables security features to make its job easier. Some viruses are specifically designed to disable security tools, giving them access to the computer’s data and private information. If an antivirus program has been disabled, it could be a sign that a virus has shut it down.

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Checking the Sent messages folder in one’s Inbox every once in a while is a smart thing to do. Some viruses gain access to a target’s contact list and send emails from their address, spreading malware to other recipients.

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A computer virus may completely block a genuine user’s access. If you realize that you can’t access your online accounts or your entire computer, this can be a sure sign that a virus is running on your computer.

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