Hello RainbowDustin, for entire drives to be accessed you need to enable both the sharing permissions and more importantly the security settings need to be changed for the drive also. Sharing entire drives is considered a security risk so Windows makes it more difficult to share them.
To share the entire drive:
Open My Computer -> right click Local Disk D or which ever drive letter your drive is using -> select
Properties -> select
Security tab -> click
Edit button -> click
Add button -> enter the name of the User you want to set Security permissions (it is the same user name you've set the sharing permissions for, ex.
Everyone will set the read permissions to every user. Put check marks in the boxes for full access and control -> click OK hit apply-> select the desired permissions -> click OK -> wait while permissions are set -> and your Done.
You will also need to use the Advanced sharing tab
Sharing>Advanced put a check in the box to share the drive, then click on the permissions tab and "add Everyone" then use the check boxes to allow
Everyone full access.
Hit the apply button on both windows.