Avira is the best ever Free antivirus that i have experienced and it provides full protection against viruses and malwares etc . It provides Three types of Protection : Real Time Protection , Mail Protection , Web Protection . By providing Mail and Web protection it ensures that your computer is free from Internet virus attack and from spam emails thus providing full protection. The main special feature of this antivirus is that it doesn’t Slow your computer and it is very simple to install and provides very simple interface access .Sometimes you may encounter some false positives too but it is provided with Ignore option that ensures that you can Ignore the threat and continue to access the file. Total scan time for whole computer is very less and fast . So give it a try and make your computer fully secured by Downloading the Free Version from here ( Download Link)

AVG Antivirus is one of the Best antivirus of all the time. It provides full protection against various viruses,malwares,rootkits and spams .It includes LINK SCANNER that scans the links that you are accessing via internet and ensures that no threat can reach to the computer and thus providing full Web Protection. AVG works silently in background without using extra memory and resources .It is provided with User friendly Interface with Modern UI .Automatic update feature updates the antivirus automatically whenever new virus definitions are available for update so you dont have to update it manually.AVG has a firewall of its own where you can select which programs you want to block or access .It is very fast and does not hang the computer at startup like the old versions tend to do .Supports touch feature in Windows 8 and interface is very much designed like the Windows 8 Interface.AVG Also provides social network protection.  Since it is a free antivirus thus some important premium features are not available but good for personal home use. You can download the free version from here ( Download Link)

Avast has recently emerged as best free antivirus since last few years providing total protection of computer against viruses and malwares. Newly designed Interface looks very attractive which is much similar to avast 6 . It is provided with various installation options like you can install it with any other antivirus being already installed on computer and will work without any problem thus providing alternate options.The interface design is very appealing and user friendly.Provides automatic update feature. Remote assistance and avast sandbox are the new key features of this antivirus.Remote assistance provides you to connect or to be connected to any other user  so as to solve each others computer problems whereas avast sandbox is a security feature that allows you to run suspicious applications in an isolated environment and the programs which you have added to sandbox have limited access to your system files so as they cannot harm your computer.Special web browser protection improvements are included to secure the computer from internet virus attack and to ensure safe web browsing.But it is reported that the scan process is very slow as compared to other antiviruses.It is fully compatible with windows 8 with windows 8 compatible updates .You can download the free version from here ( Download link)

Microsoft security essential is a free security software for Windows 7 and later versions launched by microsoft itself . Windows 8 is provided with default windows defender which is similar to Security essentials and protect the computer from suspicious viruses and threats and thus it is not available for windows 8.This security software provides better defense against malwares but is not so much effective for viruses.It provides 3 types of scan which includes Quick scan,Full scan and Customizable scan.For basic home purpose you can try this but not recommended for business purposes .If any infection is found in file then there is no option for disinfecting it instead of that it deletes the infected file .Also no firewall is provided like other antivirus.You can download it from here (Download link)