Microsoft Word 2003, as well as other Microsoft Office applications, will assist you to create typographically and grammatically correct documents. When you open a document, or as you create a document, content will be changed automatically if it contains a typo or text that could be improved upon.

What is most important to remember is this:

If something changes automatically as you type, or when you open a document, it is due to either AutoCorrect or AutoFormat, and those features can be managed using the Tools → AutoCorrect Options command. You can disable a feature so that it will no longer apply, or you can undo a change when it happens.