Have you formatted the drive already or just looked at the disk management?
If you haven't formatted it, you'll want to format it gain the "1.8 TB" access. If you did format it, you might want to check your BIOS support a 2TB drive. I know on my EVGA X58 motherboard, I needed to upgrade my BIOS to support a 2TB drive.
Exactly where do you get the ".99 Free" information? Is this what My Computer shows you as "Free Space" on a disk? Or, is it what Disk Management shows as "Unallocated Space"?
In Disk Management, Unallocated Space is NOT the "Free Space" of a "drive". It is the HDD real estate that has not yet been Allocated to a Partition. Windows treats a Partition as a "drive" that has a letter name and shows up in My Computer to use. But on a 2 TB HDD unit it is not surprising that the process of creating a 1800 GB Partition might leave a 0.99 GB fragment Unallocated.