Spyware: frequently asked questions

Applies to all editions of Windows Vista.

This page is from Microsoft. It is pasted here to avoid broken links.

What is spyware?
- Spyware is software that can install itself or run on your computer without providing you with adequate notice, consent, or control. Spyware might not display symptoms after it infects your computer, but many types of malicious software or unwanted programs can affect how your computer runs. Spyware can, for example, monitor your online behavior or collect information about you (including personally identifiable or other sensitive information), change settings on your computer, or cause your computer to run slowly.
How can I tell if I have spyware or unwanted software on my computer?
- You probably have some form of spyware on your computer if:
  - You notice new toolbars, links, or favorites that you did not intentionally add to your web browser.
  - Your default home page, mouse pointer, or search program changes.
  - You type the address for a specific website (for example, a search engine), but are taken to another website without notice.
  - You see pop-up ads, even if you're not on the Internet.
  - Your computer suddenly begins to start or run slowly.
- There might be spyware on your computer even if you don't see any symptoms. This type of software can collect information about you and your computer without your knowledge or consent. Running Windows Defender whenever you use your computer can help you find and remove such software.
Where does spyware and potentially unwanted software come from?
- Unwanted software can be installed by websites, downloaded programs, or a program you might install from a CD, DVD, external hard disk, or other removable media. Spyware is most commonly installed through free software, such as file sharing, screen savers, or search toolbars.
Can I get spyware without knowing it?
- Yes, some spyware can be installed from a website through an embedded script, or program in a webpage. Some unwanted software requires your help to install through web pop-ups or free software that require you to accept a downloadable file. However, if you keep Windows up to date and don't reduce your security settings, you can minimize the chances of a spyware infection.
What do I do when a pop-up won't close until I agree to install a program or change my home page?
- Some websites will repeatedly display pop-ups asking you to install a toolbar or change your home page. When this happens, try closing the browser window. If the pop-ups still appear, Right-click the Internet Explorer button in the taskbar at the bottom of your screen, and then click Close Group. As a last resort, close any other programs you have open, and then restart your computer.
How can I prevent spyware from infecting my computer?
- Run up-to-date antispyware software. Windows Defender, which ships with this version of Windows, helps prevent malicious software, spyware, and other potentially unwanted software or adware from installing itself or running on your computer. It can automatically find and remove malicious software that might already be installed.
- Keep your computer up to date. Microsoft often releases security updates to help prevent spyware from being installed without your knowledge. Most new antivirus programs have spyware protection, and should be kept up to date as well. We recommend that you turn on Windows automatic updating, and that you update your spyware and antivirus programs regularly. For more information, see Get security updates for Windows and Using Windows Defender.
- Review license agreements before installing software. When you visit websites, do not automatically agree to download anything the site offers. If you download free software, such as file sharing programs or screen savers, read the license agreement carefully. Look for clauses where you must accept advertising and pop-ups from the company, or that the software will send certain information back to the software publisher. For more information, go to the Windows Defender website.
How do I remove spyware and other unwanted software?
- The best way to remove spyware is to run up-to-date antispyware software that can monitor software that is trying to install itself on your computer, and also scan for and remove potentially unwanted software that might already by installed. For more information about removing spyware and other unwanted software, see Using Windows Defender and Remove spyware from your computer.