Computer viruses and worms can range from irritating to disastrous, depending on the virus or worm. Some attack your email and send thousands of virus emails from you to your list of friends and acquaintances. Some will wipe out all of your computer files; others will disable your computer completely. It is always wise to have virus protection software installed on your computer which you run regularly. Be sure to download updates from the company, as new viruses frequently invade the Internet and computers that access the Web.
One precaution: viruses and worms often arrive through email. It is recommended never to open an email and absolutely NEVER to open an attachment to an email from someone you do not know, no matter how tempting it sounds. You should also think twice about opening attachments to emails from friends when you are not sure about the contents of the attachments.
Spyware downloads programs on your computer for one of two reasons, depending on the spyware:
to direct advertising to you, whether you want it or not, often in the form of popups on your desktop, or
to steal your passwords and personal information for criminal purposes.
One way spyware gets onto your computer is if you say "yes" to seemingly innocent free offers. Accepting the free offer triggers the download of the spyware onto your computer without your knowledge. A common situation involves a popup which asks if you want your clock or weather information updated on your computer. If you say "yes," spyware is downloaded. There is spyware protection software that can be purchased which, like virus protection software, can detect and eradicate spyware from your computer regularly.