Problem:
Users is automatically locked when he/she entered 3x or more wrong username/passwor ( its depend on what you set in web.config).
Admin need manually lock n unlock Users.

Solution:
unlock is easy, cause its already buildin method for that,
hereby the sample of code:
        MembershipUser f = Membership.GetUser(UserID);
        f.ChangePassword("OldPasswordHidden", "NewPasswordHidden" );
        Membership.UpdateUser(f);

the tricky part is lock the user manually,
with this case, i used tableadapter
Select statement:
        SELECT UserId, IsLockedOut FROM aspnet_Membership WHERE (UserId = @UserId)

Update statement:
        UPDATE aspnet_Membership SET IsLockedOut = @IsLockedOut WHERE (UserId = @Original_UserId)

And for the code behind, will be:
        // create new object
        aspnet_MembershipTableAdapter user = new aspnet_MembershipTableAdapter();
        //apply Lock method       
       user.UpdateLock(Convert.ToBoolean("True"), new Guid("userID"));

 

I hope its usefull.