Just Right-click "My Computer" and select "Manage" From there, expand out "Local Users and Groups" and then click on "Users". Right click "Administrator" and select "Set Password...". You will get a warning about the possibility of loss of data (on XP). Be sure to read the warning, and then click “Proceedâ€, and type in a new password for the administrator account (twice) and click “OKâ€. Your new password will be update.