Hi FlaOpa, Dell systems come with three partitions. - First is the system reserved partition for operating system. - Second the C drive where the operating system is installed - Third is the Recovery partition. To install the Linux on the single hard drive you will have to access the Disk management in the operating system and shrink the C drive through the Disk management from which the unallocated space is formed. Then boot with the Linux disc and install the Linux on the unallocated space.
In choosing XPS 8700 hardware with Windows 7 Pro 64-bit installed by Dell (a business System), my question arose from whether can use (1)  dual boot (Windows 7 Pro 64-bit & Linux Variant) on single HDD, or(2)  if not a multi-boot with two HDDs?
How Many Primary Partitions with Windows 7 installed by Dell on XPS 8700?