It probably won't suprise you that we keep coming across people that keep all their passwords and pins in a single Word document (usually called Passwords!)
Here is a quick and simple way to protect your Word 2010 document from prying eyes:
Open your document, click on the File tab, then Info
Click the Protect Document button and then Encrypt with password.
You will be prompted twice (to make sure) - Pick a password that you will definitely remember but is really hard to guess. Tip: use numbers, letters and symbols like ? or !