How to Scan for and Remove Spyware

Scanning and Removing Spyware

Let's say you know something is wrong with your Web browser. Maybe you're redirected to a strange search engine when you really just want to go to Google. Or perhaps you keep getting buried in pop-up ads no matter what site you visit. What do you do?

The first step is to download and install anti-spyware software. There are several applications that will scan your computer for spyware. Some of them are free. Here's a short list of popular anti-spyware applications:

  • Ad-Aware (
  • Microsoft Windows Defender (
  • PC Tools Spyware Doctor (
  • Spy Sweeper (
  • STOPzilla (
  • Sunbelt Software CounterSpy (

Resist the temptation to download and install more than one application -- anti-spyware software can eat up your computer's processing power while it scans your system. Running multiple anti-spyware applications may slow your computer to a crawl. And sometimes anti-spyware applications will conflict with each other and cause your computer to crash. Check to see if the anti-virus software you use has an anti-spyware capability. If it does, you should just run the anti-virus application.

The anti-spyware software will scan your computer and look for evidence of spyware applications. Most anti-spyware applications will quarantine anything they identify as spyware automatically. Next, most of the applications will allow you to review the spyware applications found on your machine before you delete them. It's usually a good idea to delete spyware once you detect it.

The only other thing to keep in mind is that you should always make sure your software is current. If there is an option to receive automatic updates to your anti-spyware software, you should activate it. Otherwise, be sure to check with the vendor on a regular basis -- new spyware hits the Internet every day.

Once your computer is clean, you can keep it free from spyware through some careful Web surfing. Watch out for piggybacking when you install applications. Don't click on pop-up ads. And don't click on any windows that claim your computer needs a spyware scan -- doing so may actually download spyware to your machine.

Learn more about spyware and other software that goes bump in the night below.

Related HowStuffWorks Articles


  • Microsoft. "Protect your computer: Beyond the Basics." (Apr. 1, 2009)
  • Spyware Guide. (April 1, 2009)
  • Symantec. "Crimeware: Trojans & Spyware." (April 2, 2009)
  • Federal Trade Commission. "Spyware." July 2005. (April 2, 2009)