How do I know if a virus has infected my computer?

Get the basics on computer viruses: Part 2

After you open and run an infected program or attachment on your computer, you might not realize that you've introduced a virus until you notice something isn't quite right.

Here are some signs that your system might be infected:

·          Runs consistently more slowly than normal.

·          Stops responding or locks up often.

·          Crashes and restarts every few minutes.

·          Restarts on its own and then fails to run normally.

·          Applications don’t work properly.

·          Disks or disk drives are inaccessible.

·          Printing doesn’t work correctly.

·          You see unusual error messages.

·          You see distorted menus and dialog boxes.

These are common signs of infection, but they could also indicate hardware or software problems that have nothing to do with a virus. The bottom line is that unless you install up-to-date antivirus software on your computer, there is no way to be certain if your computer is infected with a virus or has some other problem. If you don't have current antivirus software installed, or if you're interested in installing a different brand, visit Security software: Downloads and trials for more information.

Related topics

To learn more about viruses, read the other topics in this series:

·          What is a computer virus?

·          How do I remove a virus?

·          How do I protect my computer against viruses?