Microsoft has just launched a re-designed, perhaps re-thought--small business center. Popular with many small business folks, this site cuts to the chase and helps small business owners get the answers they need.
Security is high on everybody's mind and Microsoft has provided a nice track for learning more about security (I would also recommend Security Awareness for Ma, Pa and the Corporate Clueless--a Business Blogging Awards winner). There is also a learning section that helps you with the information you need to know, when you need to know it.
I great place to start if you have any questions about your Windows computer or software.