In Windows Recover go to Troubleshoot > Command Prompt
it should be X: Windows\System32
type diskpart
list disk
select disk 0
list vol
you should see 3 volumes (if its not like this thats okay, will fix below)
Volume 0 C drive NTFS (won't show if broken)
Volume 1 no drive FAT32 (this is the boot drive)
Volume 3 D NTFS
exit Diskpart
type :
manage-bde -unlock C: -RecoveryPassword YOUR-48-DIGIT-KEY
this will unlock the C drive:
type manage-bde -status
change directory : dir C:\
type: chkdsk C: /f
This should repair C.
Check the volumes again to make sure they are there working.
you should see 3 volumes (fixed)
Volume 0 C drive NTFS
Volume 1 no drive FAT32 (this is the boot drive)
Volume 3 D NTFS
Now that C is fixed you should be able to use windows repair and the Bitlocker to Reset this PC>
anage-bde -unlock C: -RecoveryPassword YOUR-48-D