There is a feature in Microsoft Word which allows you to add password to your word documents. This is especially useful if the document is sensitive (such as a password list, bank details or a business proposal). If your computer is accessed by an unauthorised user, having passwords protecting your secret documents may just be what you need to maintain your privacy.
Just open Word, go to the Tools menu, select Options and then select the Security sub-tab. You will then see this box :
Enter your desired password, enter it again to confirm then press the save button at the bottom. Now next time the document is opened, the user will be prompted for the password.