NTFS drive changed to RAW

A healthy NTFS drive suddenly became unaccessable while copying files onto it. On my Windows 8 laptop under Disk Management the drive shows up as RAW.
I did a search online and someone with a similiar issue said they were able to resolve the issue using Disk Director which changed the disk back to NTFC and recoverd all the data on the disk.
I purchased Acronis Disk Director 11 for my Windows Vista desktop to try to repair this 3TB hardrive which is connected through USB 2.
On the Windows Vista desktop the drive shows up under Disk Management as "Unknown" "Not Initialized". After installing Disk Director 11 Home Update 2 on my Windows Vista desktop, the drive doesn't show up at all. When I look at "View Log" I see several entries saying Snap API drive is skipped as zero-track" followed by a message "Can not process Disc 4 because its 'sector size' is unsupported (4096 bytes)"
How do I access this drive in Disk Director and fix the RAW to NTFC problem without losing my original data?

Thanks for any help in advance!