Several Free Antivirus Programs for Windows

It is imperative that all users have antivirus software on their computers, but it is not necessary to have to pay for antivirus software. There are plenty of great antivirus software programs that are either freeware or have a shareware license that allow you to download and use the programs on one machine or all of your machines free of charge.

These programs will update their virus definitions every day and will automatically scan your computer regularly to make sure viruses aren't in memory or infecting files on your system.

Some of these include:

Avira antivirus - http://www.free-av.com - which is the current program that I use and found it catches more Trojans than any of the other programs I have tried in this article. The only major issue I have with Avira is that you get an annoying pop up several times a day asking you to purchase and upgrade your license, and the full scan can take quite long, but these are small prices to pay for a very good free antivirus program.

AVG - http://free.avg.com/ - is also another great and free antivirus software program that is an available choice for users, though I found in my tests it wasn't able to catch Trojans in real time as fast as Avira and sometimes the files that were infected wrote to the hard disk completely before they were caught.

Avast - http://www.avast.com - is another program that I used to use for my antivirus software, out of the three programs used, Avast is probably one of the simplest to install and configure though it performed the worst when running scans against my computer. Avast missed most of the Trojans and spy-ware that one of my computers picked up, that were halted and quarantined by both Avira and AVG.

ClamWin - http://www.clamwin.com - is another free open source product that you can download with an Open Source license and use freely to scanner, though this program does not include a real time scanner and will scan files only on your system.

Overall, Avira Antivirus is the winner as far as freeware antivirus programs in my opinion according to my tests, most users can safely use their windows computers with one of the first three antivirus programs and never need to have to pay for an annual antivirus software subscription.

One thing you want to make sure that your antivirus software has is the following:
Real Time Memory Scanning
File System Scanning
Automatic Updating
Trojan Recognition

Anti-Spyware - All of the above programs listed have those features except for ClamWin, but Clamwin is fast and good for doing a massive scan of all your files looking for infections (it is recommended if you want to scan a large external hard drive worth of files).