When an HDD remaps bad sectors the bad sectors are marked as unusable (and never used again!) while the data is transferred to redundant sectors sepecially reserved for this purpose. This remapping is seamless for things such as your OS and backup software so you have nothing to worry about there. :)
Ok good to hear about the Paragon backup not being affected.
Do you think I still need to download & run the program Britton30 suggested?
Plug it into any available PC to see if it's read correctly there.
Then try Disk Check . If that fails try Partition Wizard Check File System
Next try Partition Wizard Partition Recovery Wizard - Video Help.
If these all fail you'll need data Recovery. Recuva - Features
Quote