WSS (Windows SharePoint Services) not like other systems doesn't inherit permissions from
the parent automatically.
Means that even though you are site collection administrator and farm administrator
and local computer admin (even if you are domain admin…) you wouldn’t have access
to Website created under that web collection.Unless the owner (Website administrator)
gave you explicitly permissions on the Website. If the user created the Website left the
company (or was recreated for some reason) and didn’t give somebody else admin rights
on this Website you are in troubles. Recreating the user is not solution because he will get
new Sid and wouldn’t have access either.
This problem also happens after upgrading from WSS 2.0 to 3.0 for some reason the
upgrade process removes all users from the Website except from the Website primary
site collection administrator that might be an old user.
So you have to take ownership (become admin) on this website, this is how you do it:
- Open the WSS 3.0 Central Administration :Start-->Programs—> Administrative Tools—> SharePoint 3.0 Central Administration.
(By default its in “http://ServerName:17012”).
- Select Application Management :

- Select Site Collection Administrators :

- Select Change Site Collection (click on the Site Collection url to open the menu).
- Select the Website you want

- Now you can change the Website Administrator:
Good Luck !