Click the "Profile" link at the top, right of this page. It is between "Home" and "PM's"
Once you are in your Profile just enter your "Current Password: "New Password and then retype it in the "Confirm Password" boxes.
You may need to scroll down to the bottom of the page after you enter the new password information and then click "Submit".
The next change will tell you if the change was successful.
You may need to log in, at different times, if your system, or adware or virus software empties your "Cookies" or Temporary Internet files folder.
Your stored password information is stored on YOUR computer, if it is cleared then you will have to log in after it is cleared.