GRUB is the default boot loader for Linux-Mandrake 7.2. A boot loader allows you to boot into Linux or other operating systems that may be present on the PC.
The default setting shown here installs the boot loader onto the master boot record (MBR).
If you already use a boot manager which you don't wish to overwrite (such as System Commander, BootMagic, NT boot loader), you should choose an alternative location for the bootloader such as the "boot" partition or even a floppy disk.