Most of you may probably have known, while some antivirus software are free for personal use, server based programs normally will ask for a premium. Same goes to Windows Home Server. Since it’s based on Windows Server 2003, PC version mostly won’t be compatible. For an example, I am using Avast Home on my PC, but it won’t install on the server. Fortunately, there are always good people out there, especially those who write open source program, which means it’s free (they only ask users for some donation to support their hard work).