There are several indicators that you may see that would suggest that your computer has been infected with spyware or adware. Please note that some of the symptoms listed below are not exclusive to spyware or adware infections.
1) PC Performance :
Both spyware and adware consume your PC’s resources, such as computer memory. A bad spyware infection can drastically slow down your computer’s performance, even making your system increasingly unstable. Spyware can also affect the speed of your Internet connection because it takes up bandwidth to transmit information to its creator.
2) Pop-up Ads:
It is highly likely that your computer is infected with adware if you see more pop-up ads than usual. In some cases, the pop-up ads start appearing on the desktop even if you haven’t opened the web browser. Alternatively, search results may appear in a pop-up or other browser window related to the website you are visiting or the keyword terms you have entered into the search engine.
3) Browser Toolbars:
These programs often include free software, often described as “advertiser-friendly” by the publisher. The toolbar then feeds ads based on the websites you visit. They are usually very difficult to uninstall. “Search Assistant is 180” and “Hunt bar” are example programs.
4) Browser Settings :
Your Internet bookmarks or bookmarks and home page are the two main settings targeted by spyware writers. Websites are added to your Internet Favorites list in the hope that you will visit them. Browser hijackers change the home page that is seen when the browser is loaded. Any unexpected change on your home page is a sign of infection.
5) Startup Programs:
Some variants of spyware will attempt to add themselves to the list of Windows startup programs. If your startup time is noticeably slow, check your program’s startup list to find and remove unfamiliar applications. This list of programs can be reviewed using the “MS Config” option of the Windows XP Run command.
6) Software failure:
Spyware infection can cause some of your programs to crash or stop working. Look especially if your Internet Explorer browser suddenly refuses to work.
7) Hosts File Changes :
The Hosts file is a Windows file that maps numeric IP addresses to host names, just like the address book on your cell phone “maps” your friend’s name to your phone number. Some spyware programs can change this setting so that when you type “www.yahoo.com,” for example, you’re redirected to the spyware author’s website.