If i'm reading this right you had a .dbk file on your Pc you then reformated said hard drive where the .dbk file was stored which obviously deletes all data on the drive
If this is the case then there may be a very slim chance - There are many programs for recovering data from a format like Recuva etc but In my business I use Spotmau - You may be able to recover the .dbk file but if any of the in computer language 0's or 1s have been overwritten then the .dbk file will be deemed corrupted and totaly useless - However changing the .dbk extension to .rar or .zip and extracting the contents you may be able to read info like your Messages and Contacts which you could if needed retype them into your phone
