i just got off the phone with apple and they said that i am able to do a complete install with the snow leopard disc
I mean you can try, But I just had to put a new hard drive in my friends Mac and the snow leopard disk did not let me install it because there was no prior install.
Idk, maybe because I got one of the earlier ones? But I was able to do a clean install with the upgrade disk on a new HDD.