Now using a good antivirus is a necessary for all to keep their PC secure. But maximum antivirus applications are limited for 1 month use in trail period. Then you have to buy license to continue with that. But such few applications are available for 1 year with a free license. Comodo Internet Security Pro 2011 is one of them. It protects against viruses and Internet attacks for our Windows PC completely. It’s interesting feature is that Windows XP SP2, Vista and Windows 7 are supported and also both 32-bit & 64 bit versions are supported.