Kubuntu upgrade install

[Frank Arnold]

OK. I just downloaded and burnt to a CD the latest
Kubuntu Live CD. Like the look and feel of it.
My question is: If I get the install CD and run it
will it overwrite all my work related files in
my home directory or will it do an upgrade and
leave those files untouched? I'd hate to have to recreate
them. Please advise. I can back up the entire directory if necessary.
So any suggestions for a good backup procedure?
How about sources.list?
Frank Arnold