Hmm what i like to do is somthing like this (Free Handed):
'Main Form:
if(My.Settings.newuser = 1) Then 'User settings... 1 = new user, 2 = already accepted
Me.Enabled = false 'Shows the form, but its grayed out and un-clickable
Terms.Show() 'Show the agreement form
End If
'Agreement Form(On agree clicked):
My.Settings.newuser = 2
My.Settings.Save() 'Not needed, but a good idea ;D
Form1.Enabled = true
'Agreement Form(On Disagree Clicked):
Form1.Close
Me.close
Somthing like that could be an alternative to NextGen's