First download and burn the ISO image of Ubuntu 7.04 Alternate, because I found it no problems on my installtion with linux and can detect mostly all of the latest devices at http://releases.ubuntu.com/feisty/ubuntu-7.04-alternate-i386.iso
1. apt-get cdrom add
2. apt-get install ubuntu-desktop
3. apt-get update --> if you have the internet connections
4. apt-get install gdm
5. /etc/init.d/gdm start
Note:
If ever the GNOME is not successfully run try the other step
6. dpkg-reconfigure xserver-xorg
I assume that you are in the super user in doing it...