Looks like Ubuntu grub was installed in sda1 instead of sda
Windows sda5 has no boot files in it.
sda1 is Dell utility not a boot partition.
Do not usually see Windows install in a logical partition sda5 likes primary sda1, sda2,sda3 or sda4
Put in the Ubuntu Live cd and choose try Ubuntu and with internet working do this.
sudo apt-get install lilo
May show error messages about the rest of lilo missing, ignore, we just want MBR
sudo lilo -M /dev/sda mbr
Now reboot into Windows.
Put install CD back in and Choose try ubuntu and do this in a terminal.
sudo mount /dev/sda7 /mnt
Now choose ubuntu and go into ubuntu and open a terminal and:
sudo grub-install --root-directory=/mnt /dev/sda
Let us know.