What AntiVirus software should I download?

My recommendation is to use a combination of free security tools. These include Avast as the Antivirus. It's free and works very well. It is rated highly in Antivirus comparison tests. (Do not listen to anyone who suggests to use MSE. It's actually one of the worst Antiviruses you can choose) Then I recommend Malwarebytes Antimalware and SUPERAntiSpyware as secondary scanners. (Unselect free trial when installing MBAM, it's not needed) Then CCleaner for temp file removing, registry cleaning and other useful tools. Then an adblocker such as Adblock Plus or the Windows host file to block ad's. Last program I recommend is Malwarebytes AntiExploit. This helps protect against vulnerabilities in software such as Flash and Java. Use Avast Software Updater to keep up on those updates as well. Routinely scan with the programs i recommend and know what you're doing at all times and you should be able to be malware free.

What version of Windows? If it is Win 8, or 8.1 then it already has a virus scanner fully integrated into it and you do not need anything else.

If it is Windows 7 or Vista, go to Microsoft and download their free Security Essentials program.

If it is XP, good luck…

Www.free-av.com Avira best of all.

I agree with the MalwareBytes Anti-Malware (MBAM) recommendation, and strongly agree that Microsoft Security Essentials (MSE) has no business being on a (Windows Defender on Windows 8 is just MSE renamed.)

Scan with MBAM before installing any antivirus, and once a month or so It does not protect against attacks, but has detection and removal capabilities superior to the best commercial products.

Although Avast was certainly the free product of choice for a long time, BitDefender Antivirus Free provides substantially better protection with much less impact on system performance.

Avira's protection abilities have tended to vary widely with program updates, sometimes excellent, sometimes borderline mediocre.