Updating magic online with vista
The downside of this option is that you have to create a password reset CD first.
Then you can boot up with this CD and manipulate the Security Accounts Manager (SAM) database.
Not much of the original article is left except the numerous comments below.
I must admit that I managed to forget my password more than once.
Note that I published this article a few years ago, but since then I updated it several times and added a few new methods.
A detailed description of this method can be found here.
If you are uncertain what System Restore is doing with your computer, read this first. When you installed Windows XP, you had to set a password for the Administrator account.
If you still know this password, you can boot up in Safe Mode (by pressing F8 when your computer starts) and log on with the Administrator account.