Viruses & Spyware
A computer virus is a program that infects your computer. Viruses are harmful to you because they can delete files on your computer, access personal information (like credit card numbers and passwords), and allow others to access your computer over the Internet. Viruses are harmful to the network because they aggressively attempt to infect other computers, and can cause very slow network speeds for all users.
There are many types of computer viruses that can infect your computer in different ways. The most common are viruses and worms:
- A virus is an executable program that requires user interaction to infect the computer. For example, if you get an email that contains a virus, you won’t be infected with the virus unless you open the email attachment. In addition to email attachments, you can also be infected with viruses by clicking on AIM or email links, downloading infected files from file sharing programs, and by visiting unknown websites.
- A worm is a computer program that moves from computer to computer, usually without user interaction. A worm spreads by searching for security holes in a piece of software or operating system, and then infecting the vulnerable computer. Worms can be prevented by keeping your computer up-to-date with security updates for Windows/Mac operating systems, your web browser, and your email program.
- Your hard drive or memory mysteriously run out of free space
- Your computer is running slower than normal, and takes a long time to start up
- Strange dialog boxes appear on your computer
- Your virus scanner is disabled and cannot be restarted, or won’t run at all
- New icons appear on your desktop
- Windows won’t start because certain critical files are missing
- Your computer stops responding before the desktop icons or taskbar appear
- Windows spontaneously restarts unexpectedly
- You cannot start Windows Task Manager
- Antivirus software indicates that a virus is present
Keep your operating system up-to-date
As flaws are discovered in your operating system, the manufacturer will distribute patches, or critical updates that help keep you protected. For more information, see Windows Updates or Apple Updates.
Use your Antivirus Software
Antivirus software will find infected files and (in most cases) will remove viruses from your computer. It is important to regularly update your antivirus’s definitions so your antivirus knows how to spot the latest viruses.
Use safe computing habits
The first line of defense against viruses is you. It is crucial that you keep your computer current with operating system updates and virus scanner definitions! In addition, you should scan all e-mail attachments, and think twice before clicking a link in your instant messages – many new viruses are spread this way. For more safe computing recommendations, see the Security page.
If you don’t have antivirus software, you will need to get one. There are various free options for antivirus software available on the internet. Some of the popular choices are Microsoft Security Essentials, Avira, Avast!, and AVG Free.
Virus removal and tools
If your antivirus software is not removing the virus, or the virus reappears when you restart your computer, here are some additional things you can try: