A partition is a boundary on your computer's storage medium (the hard disk). Strictly speaking it is a logical portion of a hard disk to which you assign a drive letter (eg C:) or mount point. Microsoft defines the boot partition as the partition which contains the files that allow your computer to boot to the operating system. For windows XP they include the files boot.ini, NTLDR and Ntdetect.com. The system partition is the partition which contains the operating system files ie the /WINNT folder. In the vast majority of cases, the boot and system partitions are the same ie C:. I expect you have installed the game onto the C: partition which is both the boot and system partition.