When I close Word, it asks me whether I want to save changes to Normal.dot. What is Normal.dot, and why is it doing this to me? I haven't done anything to it.
You probably have done something to Normal.dot, but only inadvertently. Normal.dot, also called "the Normal template," is the default template on which Word bases documents unless you tell it to use another template. In addition to typical template items such as styles, page margins, and default font and paragraph settings, Normal.dot contains your formatted AutoCorrect entries and your AutoText entries. It's also a convenient place to store VBA items such as macros and user forms.
If you've created a formatted AutoCorrect entry or an AutoText entry, or if you've changed your default font, page layout, or paragraph settings, you've changed Normal.dot. Similarly, if you've created or installed a VBA item, you may have changed Normal.dot. If Word prompts you to save it (see Figure 1-7), click the Yes button.
Figure 1-7. You can prevent Word from prompting you to save Normal.dot.
If you're not aware of having made any such changes, it's possible that your computer has a macro virus that has made a change against your will. If so, you won't want to save changes to Normal.dot. Check your computer for viruses immediately.
If you want Word to save any changes to Normal.dot automatically without prompting you, choose Tools » Options, click the Save tab, and uncheck the "Prompt to save Normal template" box.