New Seagate 3T external HD came with 2 partitions: 2048 GB and 746.52 GB. Larger partition formatted NTFS. Smaller partition says "Unallocated" and will not do anything. Larger partition will not extend to include the second partition. Second partition will not format and become a "Simple Volume". Is this an MBR/GPT problem or someting else? What do I do to use the second smaller partition?