How to prevent accessing a pendrive?

Hello,

I want to prevent accessing a pen drive from My Computer i.e explorer.
For this i handled "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer" by adding a new DWORD value NoDrives by applying a nodrive value..
I succeed this step.

But still the pen drive can be accessed from the address bar in the explorer window. like......
F:\ this displays the contents of the pen drive. how can i disable this feature using registry.