Restrict access to hdd or partition in windows 8 to admin only
The answer is actually pretty simple.
1 - Right-click the drive of choice in Computer
2 - Properties
3 - Security
4 - Update access as needed. (In this case, removed "Users")
Taken from "grawity's" post on this link that wasn't chosen as the correct answer, but it definitely is in this situation.
Thanks to yassarikhan786 for pointing out a similar question.