You probably have the rest of floating at the end as an unassigned partition.
Use windows administrative tools to fix the issue (at the very least to inspect the details better than speccy will)
Specifically Administrative Tools > Computer Management > Disk Management
From there you should be able to see the full volume in all its assigned/unassigned partitions and correct any issues from there.
If it is unassigned.. simple right click the unassigned portion... mount the volumes remaining space and format it and it will be accessible.
PC Setup:
Battlestation Setup:
