I unintentionally set a password that I don't remember

I often get a message that I must submit permission to perform some action like delete a folder. Apparently I unintentionally set a password that I don't remember for the administrator account. Fortunately this is on my laptop which has no important files that are not also on my desktop so losing data is not a huge issue. I want to try the steps in the tutorial Brink suggests but I don't see an administrator account in the user accounts but there is a folder for it. I'm kind of lost at this point about where to work on the problem.

BTW: This is one of those machines that came with Vista with a free upgrade to Win7 so I don't have Vista installation disks.

Enable the real hidden Administrator account as follows:

Open a Elevated Command Prompt. Click Start, All Programs, Accessories. Right click on Command Prompt and select Run as Administrator.

Enter net user administrator /active:yes and press Enter
Type exit and press Enter to close the Command Prompt window.

Click Start then click the Arrow to the right of Shutdown and select Logoff.
When the Login screen is shown, is Administrator there? If yes, click on it to login as Administrator (no password).

If not, login as yourself again then do a Restart.
Press F8 during Restart to bring up the Advanced Boot Options menu. Select Safe Mode.
Login as Administrator (no password).

Open Control Panel then User Accounts.
Click on Manage another account

Select the account you want to add or remove a password for then click on Change password or Remove password.