Depending on you BIOS (PhoenixBIOS, AWARD,etc), you need to go to the manufacturer's website and download it. Hope that the power doesn't go out during the BIOS upgrade, otherwise you're done.
My guess is that BIOS looks at it and it has more space than it can address in the BIOS. Some have a limitation of 2GB, 4, 10GB, etc.... If it doesn't detect it, that's why.
Try going to the type, hit user, and use the numbers from your HDD label to get a somewhat close picture of the drive's size to your BIOS.