Hello ShermanKim, and welcome to Vista Forums.
Did you forget the password for the administator account, or just do not have one?
If you do not have an administrator account that should have been created apoun installing Vista, then you should be able to create
one once you boot into Safe Mode
and log into the built-in Administrator account
If there is an administrator account on the computer that is password protected, then you will not be able to do this since you will need that account's password to enable the built-in Administrator account. If there is not one, then Safe Mode should boot directly into the built-in Administrator account.
Hope this helps,