I may be mistaken and if I am I know someone will come behing me and correct, but by default, there is no password on the Administrator account.
Log onto your computer normally, goto your control panel, click users and the Administrator account, if it's not there, you will need to enable it, then go to the Administrator properties and click change password, if you did not put one in before it will ask you to input a new password.
After that you should be good to go. -- I think.... lol.
You could say I've been around.