Some indications that your PC may contain spyware are:

• Poor system performance, especially while browsing the Internet.
• The PC stops responding more frequently.
• The PC takes longer to open the Windows desktop.
• Browser closes unexpectedly or stops responding.
• Performing a search from a search page provides results on a different site.
• Clicking a link does nothing or goes to a non-related Web site.
• Browser home page changes and may not be able to be reset. Usually, about:Blank is set as your new Home page.
• Pop-up advertising windows appear when the browser is not open or over Web pages that do not normally have pop-ups.
• Additional toolbars are added to the browser.
• Web pages are automatically added to list of favourites.
• Desktop icons are automatically added to the desktop.

What is Adware?

Adware is software that displays advertisements on your computer without your permission, even if you're not browsing the Internet. Adware helps some developers recover programming development costs, and it may allow the software to be provided to the user of the application free of charge or at a reduced price: due to the advertising, the programmer may still profit from the wide use of their work, motivating them to write, maintain, and upgrade the software product. There are concerns about adware because it often takes the form of spyware in which information about the user's activity is tracked, reported, and often re-sold, often without the knowledge or consent of the user.

What is Spyware?

Spyware is any technology that aids in gathering information about a person or organization without their knowledge or explicit permission. Spyware silently transmits user information via the Internet to advertisers. In addition, Spyware can cause your PC to perform very poorly (slow browsing and downloads, program crashes etc). Spyware may be found:

• Bundled inside of shareware or freeware applications.
• In free versions of otherwise licensed applications.
• In peer-to-peer (P2P) and other file sharing programs

What is browser hijacking software?

Aggressive advertising software programs that change the settings of your browser without your knowledge. These can be very annoying and may appear as a virus at first (slow Internet connection and lots of network activity).
Typical changes from hijacking software are:

• The browser's home page address.
• Search bars.
• Tool bars.
• The creation of desktop shortcuts.
• Intermittent advertising pop-ups.

Once a browser is hijacked it may also redirect links to other sites that advertise or collect your usage information.