Make Your Hard Drive Inaccessible

Go to the registry editor
navigate to the following place..

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
In the right hand pane for the Explorer key, create a new "DWORD" value named ViewNoDrive


Double click the new value and enter the value as.......

for hiding A drive set value as 1 , for B its 2 and C its 4 and so on and for Z its 33554432

generally multiply it by 2 for the next alphabet to hide.
Once done, reboot or log off and login in again. Then try double clicking the drive you made inaccessible.
You should receive a message stating that the drive cannot be accessed