How do I password protect a Word 2003 Document?

Put it in a separate folder and pwd protect the folder by right clicking and going to properties and/or sharing/security.

In MS Word 2003 - Tools - Protect Document - Supply a password.

This is from MS Word 2000 Help, but I imagine that your version will be similar:

Open the document.
On the File menu, click Save As.
On the Tools menu in the Save As dialog box, click General Options.
In the Password to open box, type a password, and then click OK.
In the Re-enter password to open box, type the password again, and then click OK.
Click Save.

Depends on what OS you are using. If you're using XP Home, then you'll have to use some kind of software to password protect the document. WinRar will let you password protect your file.

Follow :
Set a password to modify a Word document

1. Click the Microsoft Office Button , click Save As, and on the bottom of the Save As dialog, click Tools.
2. On the Tools menu, click General Options. The General Options dialog opens.
3. Under File sharing options for this document, in the Password to modify box, type a password.
4. In the Confirm Password dialog, re-type the password. Click OK.
5. Click Save.

Create a password to open

In the Password to open box, type a password, and then click OK.
In the Reenter password to open box, type the password again, and then click OK.

Create a password to modify

In the Password to modify box, type a password, and then click OK.
In the Reenter password to modify box, type the password again, and then click OK.