I think you guys didnt get my problem.
Its not about the 2 TB, its about that my computer doesnt even detect the HDD and not even my old HDD (SATA II)
In that case you most likely have a faulty motherboard.
Disconnect all drives, remove the battery from your motherboard and clear the CMOS.
Reinsert the battery, connect 1 of your drives and see if it is recognized in BIOS.
Your motherboard has 6 3Gb/s ports. Try your drive in all 6 ports.
If the drive is not recognized try your old drive in all 6 ports.
If both drives are still not being recognized your motherboard needs to be replaced.