Don't enter any text in the entry box. Click now on the Replace With entry box and type a few spaces. Now click Close. You have just destroyed your document by replacing all the Normal style text with spaces. If something like this should happen to you, don't panic.
Panic is what causes permanent data loss.
In this case, all you have to do is press Ctrl-Z and, thanks to Word's terrific Undo command, your document will magically reappear. The moral is, be careful with Replace All. With unless you're sure this is what you want. And never forget that wonderful Undo command. John Shults Sr.