Microsoft Office is a small business staple, but if you’re still using Office 2003 (and plenty of offices are), take heed, because Office 2003 documents use a binary file format that can execute potentially malicious code when you open them. The XML file formats used by the newer Office 2007 and 2010 versions, on the other hand, greatly reduce this problem, and Office 2010 includes a Protected View that opens potentially risky files — such as email attachments and files downloaded from the Internet– in a read-only mode.