If you remove the logical drives, the extended partition and the parimary partition, you should then be in the position of being able to access the full capacity of the drive. The terminology can be confusing. You can create only one primary partition. The remainder of the drive can then be used to create an extended partition. Within the extended partition you must create logical drives. You can have as many logical drives as you want, just be sure that you use all the available space within the extended partition. Thus, if you wanted 3 partitions then the primary partition would be the C: drive and within the extended partition you would create two logical drives, D: and E:
If the above does not resolve the problem I would go to the HDD manufactures web site and see what utilities they have available for download . Fox example, Western Digital has a utility called Data Lifeguard Tools.