If your computer is runing slowly for some unexplained reason, and you've tried scanning for and possibly removing viruses to no avail, you may be a victim of "spyware". Ad-Aware by Lavasoft removes malicious Adware, Spyware, Trojan horses, Trackers, Hijackers and Dialers. They provide a free version for personal use, as well as several levels of commercial solutions from small business to enterprise level.

Many traditional virus scanners, aside being not very effective at their own job, are particularly ill-suited to removing non-viral malicious software, also known as malware (are you having fun with all of these different classifications?). Ad-Aware is one of the legitimate answers to this problem. There are many more programs which are not only not terribly effective, but sometimes contain spyware themselves. Others merely rip off a legitimate program's spyware database and sell it as their own solution.

Ad-Aware is one of the pioneers, and we have used it extensively to remove malicious software from residential computers.

Spybot Search & Destroy detects and removes spyware from your computer. This software is completely free, which is helpful to small businesses who are often already burdened by the cost of Antivirus solutions. Spybot can run in two modes: Easy mode with basic features, and Advanced mode with additional features. Though Advanced may scare you away, we recommend using it over the easy mode, as even looking at the extra sections available can help you determine if you are still having a problem.

Download free anti-virus software from Grisoft AVG. Most Antivirus software is too expensive, especially for home users. The newest version of the popular AVG Anti-Virus Free Edition is available for download. The free version is available to home users, while there is an more robust solution for home or office users that offers a free trial. Until products like Comodo Antivirus get up to speed, AVG Professional Edition for non-personal/home use is a good buy in our opinion, offering a $38.95/2 year subscription for a single user.