Validation Inside Classes

I'm currently new to OO programming with Classic ASP and have been stopped dead in my tracks on the issue of validation inside classes and if I should be doing things that way. I have been using a User class and it has methods such as Save(), Update() and Delete(). Particularly with the Update() method I'm unsure if I should be validating my form(s) within the class or on the actual edit.asp page that uses the Update() method?

I have two types of edit pages; one for Admin users and one for the My Account page. On the My Account page if the user wants to change their password they have to enter their current password, a new password and then their new password again to confirm .

If an Admin user is updating that same user's info they do not have to go through those steps and they can simple just change the password by typing it in. The point here is that there are two separate cases of validation rules on two separate pages that both use the Update() method. Do you validate your forms inside your classes or outside?