If you can obtain a copy of the Ultimate Boot CD, or perhaps ERD Commander 2008, run the Locksmith utility. This will allow you to change the password on one, and only one, account. I believe you, that you know what you're doing, but this will be a very quick and easy way to make absolutely certain you are typing the password you've assigned. (It's also a fantastic tool to have in your aresnal.)
I've used both of these apps, religiously, in the past, and they have saved my bacon many times over.