According to Digital Inspiration that’s the case if you are using Windows XP because leaving the password blank makes it impossible to connect to the computer remotely. The link given in the article which points to the Password Strength & Password Security page at Microsoft.com is unfortunately not available at this point.
How to display all Windows passwords
Just a few days ago I was describing a method that would allow anyone to change passwords for all windows accounts using a boot cd and a program called NT Passwords. This is great if it does not matter if you change the password for, lets say, the administrators account. It might however be sometimes important to get into an account without the owner of the account knowing – and he would surely find out if his password would not be working anymore.

