Your hard drive is partitioned into 2 logical drives. If you didn't partition it, did someone else "repair" on your computer for you? You can still add another drive in your open bay. If it is just additional data, it will most likely install as dat...

I have the same G75VX BH17N11. The HDD controller is SATA 3 and will run 6 GB/s if the drive is capable (like a SATA3 SSD). The standard ST1000 is a SATA 2 drive and as such has a 3 GB/s rate even though the controller is SATA 3.Hope this helps.If th...