It is recommended that you change your password regularly (at least once a month) to keep your system information secure. It is also recommended that you use "strong" passwords. To create a "Strong" password, you can use this free tool:

To change your Windows Vista password:

• Press CTRL + ALT + DELETE on your keyboard.
  

• Type in your old password, then your new one twice in the supplied text boxes.

• Press Enter on your keyboard.