1) Unresponsive Functions - If opening certain tasks delivers no response, it obviously implies there is a spyware infection that disables the operation of software in normal mode. The more time a spyware or virus infects the system, the more applications it can disable and make unresponsive until all software programs stop performing.

2) Illegal Bookmarks and Unknown Links - The inclusion of bookmarks, favorites, and links that start to appear in your web browser can also be a huge warning sign that spyware has infected your PC. The spyware will make unfamiliar and unknown links in the web browser's favorites and bookmarks options, pressing one of which leads to bigger more severe problems. It is advised then to run an anti-virus program to identify the threat right away.

3) Suspicious Toolbars - One more integration of malware in your web browser is that of toolbars. You may know of Yahoo, Google, and MSN toolbars that actually help, however the inclusion of certain suspicious toolbars in the web browser is an indication that some malware is recording your browsing history and transferring this information elsewhere.

4) Email Bombs - These email bombs are one of the final hints that malware has taken over the Operating system. Lots (and I mean lots) of unrelated emails and explicit material inside your inbox, indicates that your operating system is significantly infected and requires a scan and cleanup. This actually works both ways; the emails don't just come into your inbox but additionally send automatically to all or any of your email contacts so it is encouraged to check your sent messages in such a case. Treat your password like your toothbrush. Don't let anybody else use it, and get a new one every six months. Clifford Stoll

5) Fake Warning Messages - While infected, the operating system starts displaying odd and fake warning messages stating that the PC is infected with spyware and it suggests using a certain anti-virus program that will clean the PC from the infection. But, this software is really a gimmick which furthers the problem with more spyware to steal your personal data. None of these offers should be followed and really should be responded by disconnecting the computer from the web and running an immediate scan ideally with an updated version of an anti-virus. This symptom is serious and procrastinating cleaning your computer at this point usually results in even more serious troubles.

6) Web browser Redirection & Pop-ups - A probable sign that the PC is infected is the internet browser being redirected to an unrelated web page that basically wants you to download some software or participate in a survey. When you enter a URL or go to a search engine, the exact same website will pop up no matter what you type in. Pop-ups have a similar resulting effect. You may have proper browsing, but before too long the browser opens a pop-up window that has explicit or unrelated content that you never requested or wanted to open up. Disconnect yourself from the internet and run a thorough scan. NEVER click any of the pop-up windows, since it will undoubtedly make the spyware threat escalate.

7) Sluggish System Performance - The most apparent factor that proves the computer is infected is the sluggish overall performance of the operating system; programs open slower and run slower also. Opening up a Microsoft Word document might take 5 to 6 minutes and such, is a definite warning that the Computer is infected