How to Determine if Malware is on Your Computer

by Contributor

Before you can determine if you have malware on your computer, you first need to understand what malware is. Malware is the nickname given to any type of malicious software--software that is created to cause harm to a computer or the owner/user of the computer. Malware includes spyware, viruses, worms and Trojan horses. There are ways you can determine if you have malware on your computer.

Become familiar with your computer. Knowing what is "normal" is very important; if you don't know what is common for your computer, you won't know what is not normal.

Watch for signs such as pop-ups when you're not surfing or even connected to the Internet. Home page changing and unexplained programs loading at startup could mean you have spyware on your computer. This form of malware is most commonly just annoying, but it can also be dangerous as this is taking control of your computer.

If your computer freezes up (doesn't respond), restarts on its own, programs don't work right or you get strange error messages, your computer may have a virus. It is possible there is simply a tecnical problem with a program, but these are also signs of a virus.

When a computer starts to run extremely slower than normal, available disc space is very low for no reason, or programs start responding strangely or not at all, you may have a malware on your computer called a worm. Worms are dangerous because they reproduce themselves, distribute themselves to others (such as everyone in your address book), and can install on a computer without you doing anything at all.

Trojan horses, or backdoors, can be the most damaging malware and at the same time the most difficult to find or detect. Although some backdoors will do things such as delete files or change file names, the really bad ones just sit quietly in the background and do just as the name suggests: give someone access to your computer, your personal information, passwords and account information.

One of the simplest malware programs is the "browser hijacker." This form of malware will add tons of pop-ups, change a home page and/or redirect your surfing to Web pages of their choosing. Some browser hijackers will also add bookmarks to a favorites list.

If you received messages in your email that say something like "an email was undeliverable" and you didn't send an email to that address, there is probably a form of malware on your computer sending itself to other computers.


  • check Install a reputable anti-virus and firewall to help stop the installation of malware on a computer. These programs must be kept updated regularly for them to work effectively.
  • check Don't store account information or passwords on your computer.
  • check Don't enter personal information, such bank account numbers and passwords, on sites you did not personally type the url into the browser.


  • close It is becoming more difficult to determine which particular form of malware is installed on a computer.
  • close There is a rash of spam mail being sent out saying things like "your account has been accessed" or similar wording. The goal of these emails is to get you to respond by going to a Web site to log in to bank accounts and such. These sites are hiding behind official sites and are collecting account ids and passwords. Always type in the url of such sites yourself, don't click on the link in an email.

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