More is always better, right? Well, in most cases it is. However in terms of using anti-virus protection for your computer, one is enough. While certain programs may have better or different catch rates (How often the program detects issues), or less “false positives” (When a file is incorrectly marked as malicious) and so forth, you do not want to mix these programs together!
If you find a better antivirus program than the one you are currently using, whether it is your personal computer or on a set of computers you administrate – you want to remove the existing program first. On the outside, it sounds ideal to combine products to maximize your protection but what this actually does is increase the strain on your computer greatly.
Think of it in this way – an antivirus program would be similar to an army of medieval knights and your computer is comparable to being your castle. Your army will tirelessly and vigilantly protect the entrances to your castle, while also searching the premises for unwanted things that have snuck by occasionally. Introducing a second antivirus program to your computer would be identical to hiring a new and completely different army while simultaneously employing both to do the same job.
These armies will constantly bicker with each other and try to gain each other’s ground. One army has an entirely separate approach to deal with threats than the other while both defend your data differently. An antivirus program sets up its own system and methods of computer protection. They generally do not like interacting with each other, and your computer’s safety becomes an issue once again. There are further side effects of using multiple programs to achieve protection from viruses, but the main trouble would be programs trying to dominate one another.
Other programs cause fewer issues – something along the lines of anti-malware, or anti-spyware programs. These are suitable to use in conjunction, and are lighter supplements to your total defense plan. It is just the heavy defenders like Norton, AVG, Kaspersky, Avast, Avira, and so forth that do not play nice with each other. Ideally, the ultimate goal for protection is to find one you like with reliable results, and let it operate only with complementary programs.
If you are currently unprotected, we highly recommend getting some form of security, and there are some great free programs. For an antivirus, try using AVG (http://free.avg.com) or Avast! (http://www.avast.com) These are safe and free to download. We also recommend a few additional programs like Malwarebytes Anti-Malware (http://www.malwarebytes.org) and SUPERAntiSpyware (http://superantispyware.com). These tertiary programs specifically target other sources of malicious files.