To utilize all 3TB you need to use GPT partitions, not MBR. If this will be a boot drive, you will need the 64 bit windows 7 and a UEFI motherboard.
Q. Can Windows 7, Windows Vista, and Windows Server 2008 read, write, and boot from GPT disks?
A. Yes, all versions can use GPT partitioned disks for data. Booting is only supported for 64-bit editions on UEFI-based systems.
http://msdn.microsoft.com/en-us/library/windows/hardware/gg463525.aspx#X-201104111922342