FAQ > Keeping Your Computer Healthy > What anti-virus software should I have?
If you are using Mac OSx, use the top selling anti-virus program in the Mac Store if you have concerns, but most Mac computers do not really need any anti-virus software. If you are using Linux, I would not worry about viruses at all.
Microsoft began offering free, comprehensive anti-virus protection via "Windows Security Essentials". This will automatically update and offer the same protection as programs that have a fee associated with them. You can get it here: http://www.microsoft.com/security_essentials/.
If you have reason to believe that one of your computers has been infected with a virus, malware, spyware, etc. and you want to be certain, I recommend running the anti-virus scanning feature of the Trinity Rescue Disc. This process often takes several hours, but it is free, uses 3 anti-virus programs and will generate a report showing what viruses the computer has.
You can download the Trinity Rescue Disk here: http://rm.mirror.garr.it/mirrors/trk/trinity-rescue-kit.3.4-build-367.iso.
This file is an .iso file, which means it is the image of a disc. You must then burn the .iso image to a CD. Do not burn the .iso file to the CD, but use software that lets you make a CD from an image file. Your computer may already have software that can do this or it is built in to most modern operating systems (Windows 7, Mac, Linux, etc.).
Once you have made a Trinity Rescue Disk, restart your computer and boot from the disk. Once the Trinity Rescue Disk menu appears, select the option that will scan all of your computer's drives automatically. If your computer is connected to the internet via a network cable, the software will automatically update itself so it can scan for even the latest viruses.
The Trinity Rescue Disk will not modify anything on any of your hard drives and, since it runs from a CD, you are not putting the potentially dangerous computer into contact with your network, other computers, or any portable media. Once the scanning is complete, it will display a report of any viruses found.