To change the Administrator password in Windows Server 2003
Log on to the computer using the Administrator account.
Click Start, right-click Administrative Tools, and then click Open. Administrative Tools opens.
Double-click Computer Management, click Local Users and Groups, and in the details pane, double-click Users. The Users folder opens.
In the details pane, right-click the account that you want to change, and click Set Password. A warning dialog box opens. Read the information to determine whether you want to proceed with the step to change the password.
In New Password, type a password. In Confirm password, retype the password, and then clickOK.