How to add new songs without erasing the old. how to add new games, photos, contacts, vedios. whts the use of radio.

I have no idea how to add anything but the songs and videos and I recommend SharePod.
SharePod is a complete standalone program that can run from the ipod. You will need Netframe work 2.0. The links are below. They go right to the download link on the website so you don't have to hunt for it.

SharePod:
http://www.getsharepod.com/download/

Net Framework 2.0:
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=0856eacb-4362-4b0d-8edd-aab15c5e04f5&displaylang=en

How to add Videos and Songs:
First download and install Net Framework 2.0 if you don't have it.
Next Open the Sharepod zip and copy and paste the program where
you want it.
Then open Sharepod.

Sharepod:

For Music:
1: Find the Music you want to add on you computer and right click the folder
and copy the name.
2: Open sharepod and go to the bottem left and click playlist.
3: Right click New Playlist and paste the name you copyed.
4: Click on the (Copy to ipod) icon at the top of the screen.
5: Click add folder.
6: Navigate to the file where you music is and click ok.
7: Click ok again.
8: When the file are finished Drag the select file to the proper playlist.
9: You have just added your music without deleteing anything. Enjoy.

For Videos:
1: Open sharepod click on the (Copy to ipod) icon at the top of the screen.
2: Click on Copy File.
3: Navigate to the File click Ok.
4: Click ok again.
5: Enjoy

Eject your ipod and enjoy.

Good Luck and Enjoy