The Microsoft Office team has done a fantastic job in recent years. Their launch of Office 2007 is biggest benchmark for their success. Install rates are high and so is customer satisfaction (wish the Microsoft Vista team could say the same). With the success of Microsoft Office comes that awkward stage in technology when some of us are using Docx files and others are using the tried and true Doc file. What's the difference? Docx files are generated by Office 2007 and Doc files are generated by older versions. This isn't an issue unless you are still running an older version in which case you cannot open Docx files with a handy double-click of the mouse.
Here are your options:
1. Install the Microsoft Office Compatibility Pack for 2007 File Formats. Here are the instructions from Microsoft. Good luck with that.
So, while we sit in technology limbo with half of us using Office 2007 and half of us using an older version of Microsoft Office we will have to deal with file compatibility issues. Make your life easier and use one of the options detailed above if you find yourself in a jam.