To install ubuntu on Dell system you need to change the default boot loader to grub2 or something else
#change the root password to something that you know
sudo passwd
#become root

mkdir /media/ubuntu
mount /dev/sda1 /media/ubuntu

# check that you have mounted the right partition.
ls /media/ubuntu

mount -t proc none /media/ubuntu/proc
mount -o bind /dev/ /media/ubuntu/dev
cp /etc/resolv.conf /mediaubuntu/etc

chroot /media/ubuntu /bin/bash
/etc/init.d/networking restart
aptitude update
aptitude install grub2