alternative cd for edgy

[MICHAEL WEAVER]

I have just burned the Alternative CD for Edgy.
If I use it to install Edgy will it overwrite everything I already I 
have on my laptop including my sources.list file?
I ask because at the moment I have Dapper on my Laptop and made changes 
to that file in order to get Orca at a time when getting Orca was 
difficult because at that time I got Luke's packaged version of Orca 
which might explain why I couldn't upgrade from Dapper to Edgy using apt.
What I am trying to say is will the etc/apt/sources.list file be 
modified to the default file for Edgy, overwriting any changes I had 
made in Dapper to obtain the packaged version of Orca from Luke's web 
site when I do an install of Edgy from the Alternative CD with a fresh 
etc/apts/sources.list file like you might get if you had done an 
installation of Edgy without upgrading from Dapper to Edgy or will my 
changes in that file be kept whether they affect that file or not which 
may cause problems?