@sangell,
it should automatically detect your hdd when you put one.
i did not do anything with the bios when i got my 2nd hdd.
but for the sake of making sure you can check it as well.
ASUS G75VX-T4072H The Ultimate Fighting Machine 😉
Intel® Core™ i7 3630QM Processor
Windows 8
16GB DDR3 1600 MHz SDRAM (Hynix+Kingston)
17.3" HD+ EWV (1600 x 900)/Full HD (1920x1080)
NVIDIA® GeForce® GTX 670MX with 3GB GDDR5 VRAM
Hitachi 750GB HDD
Western Digital Scorpio Blue 1TB HDD
Super-Multi DVD
Noob Gamer but Loves to Play Games. 😄