So, how many physical HDDs are in your system? Also, what OS are you using? Your solution depends on these answers. Please claify and I am sure someone on Tom's can help.
BTW, when you reformatted your entire system, did you delete and then create new partitions as well? If so, you may have went from more than one partition to a single partition, overwriting your previous data in your D: drive.
If that is the case, you may need to find some partition recovery software, like Recuva (http://www.piriform.com/recuva) to get your files back.
Please answer the questions above and we'll see what can be done. Good luck!!!