Since hackers are well aware of the C$, D$, etc. shares, these shares can pose a security risk on your systems. But deleting the shares creates its own problem: Every reboot re-creates them.
To disable the shares altogether, you can make a change to the registry. Follow these steps:
In addition to disabling shares, you can also hide any share that you've created from the network browser with a simple keystroke. Just as you can hide the IPC$, C$, and other administrative shares, you can hide a user share by adding a dollar sign [$] at the end of the name.
By doing so, you hide the share from anyone browsing in Network Neighborhood, but you can still map to the share by typing its name directly. You can use the same trick for hiding an NT printer share.
Note: Editing the registry is risky, so be sure you have a verified backup before making any changes.