Windows Vista Security basics - Understanding security and safe computing - Use spyware protection

Spyware is software that can display advertisements, collect information about you, or change settings on your computer, generally without appropriately obtaining your consent. For example, spyware can install unwanted toolbars, links, or favorites in your web browser, change your default home page, or display pop-up ads frequently. Some spyware displays no symptoms that you can detect, but it secretly collects sensitive information, such as which websites you visit or text that you type. Most spyware is installed through free software that you download, but in some cases simply visiting a website results in a spyware infection.

To help protect your computer from spyware, use an antispyware program. This version of Windows has a built-in antispyware program called Windows Defender, which is turned on by default. Windows Defender alerts you when spyware tries to install itself on your computer. It also can scan your computer for existing spyware and then remove it.

Because new spyware appears every day, Windows Defender must be regularly updated to detect and guard against the latest spyware threats. Windows Defender is updated as needed whenever you update Windows. For the highest level of protection, set Windows to install updates automatically