NOTE: If you'd prefer to view this information as a blog post, check out this entry in our Five Apps blog.
Protecting a PC against malicious software is a never-ending battle. The second you think you have your machine clean, something else appears -- no matter what piece of software you use to combat this plague. Even so, you still need to have some protection installed. Here are the five tools I prefer for keeping Windows as malware-free as possible. They don't cost a dime, and they're about as reliable as a malware removal tool can be.