Windows Tips: Security Is Up to You--Perfect Your Passwords
Dunn's third law of PC security states: The older the password, the less secure the system. (The first two laws are "Never assume your data is safe" and "If it's from Microsoft, it has holes.") The simplest and cheapest way to safeguard your information is to put a little thought into your passwords, keep them fresh, and use them always.
For the basics on Windows passwords, read my column from September 2002, and see Scott Spanbauer's take on effective passwords from his October 2003 Internet Tips. The following tips enforce best password practices, though some of them don't apply to PCs on networks whose administrators use their own password policies.