Ok, I will make a little shorter now.
The kernel that is used on your system can be found at:
Here, select the correct hardware you have and select the latest kernel.
Save the package to /home/user, so you know where to find it. If you use easy mode, use ctrl-alt-t to open a terminal, otherwise you can use the 'launch button' and look under applications (I believe, I have no xandros anymore as I am building an LFS system on my eee. look around for it in the menu, it may be called a console)
Next, unrar, install the package and unpack the tarball:
unrar x Linux_Kernel_071127.rar
dpkg --install linux-source-18.104.22.168-eeepc_5_all.deb
tar xjvf linux-source-22.214.171.124-eeepc.tar.bz2
You are now in the directory where you have the sources. You must exit, in order to prevent being root for too long.
To do anything with them, make sure you have the development tools.
add to /etc/apt/sources.list:
deb ftp://ftp.nl.debian.org/debian stable main contrib non-free /* it is better to find a mirror near you */
sudo apt-get update
sudo apt-get install build-essential
Hope this helps.