Completely removing Office 2008 and reinstalling it is quite a drastic move to be the first thing on the troubleshooting list. I would highly recommend not going through the pain of uninstalling and reinstalling the entire Office suite in order to solve a small margin problem.
It's likely that the default Word template somehow got the margins set at 14", and therefore all new documents inherit this margin setting.
First, let's try opening and adjusting the default template for Word documents:
- In the Finder, navigate to: /Users/yourusername/Library/Application Support/Microsoft/Office/User Templates/My Templates
- Double-click "Normal.dotm"
- Adjust margins to your liking
- Save and close the "Normal.dotm" document
You can also just delete the "Normal.dotm" file, and Word will create a new, default one the next time you launch it with all of Word's default margins and settings (I recommend deleting the file while Word is not open).
If you require Word to communicate/collaborate Word documents with Windows-based computers that are running the Microsoft Office system, I would recommend staying away from the iWork suite, as it is not as compatible with Windows-based Office documents as Office 2008 is, and in addition, it is not nearly as powerful as Word is. While iWork is a great package, it hardly stands on its own as a fully-featured Microsoft Office replacement.