We are upgrading one stand alone computer. We currently have Autocad 2006LT. Originally we had Autocadlt 1997, then upgraded to 2002lt, and finally upgraded to 2006lt. We have the 1997 CD's and the 2002 upgraded CD's. However, we do not have the 2006 upgrade CD as we downloaded it off the internet. We have not put anything on the new computer yet, what is the best way to get 2006lt onto the new computer?