This is yet another trick you can play on your friend. To disable the display of local or networked drives when you click My Computer go to :
Now in the right pane create a new DWORD item and name it NoDrives. Now modify it's value and set it to 3FFFFFF (Hexadecimal) Now press F5 to refresh. When you click on My Computer, no drives will be shown.
To enable display of drives in My Computer, simply delete this DWORD item. It's .reg file is as follows:
You need to keep one thing in mind. Whenever you make changes to the Windows Registry you need to Refresh it before the changes take place. Simply press F5 to refresh the registry and enable the changes. If this does not work Restart your system.
Moreover you are doing this at ur own risk..if anything goes wrong i may not be held responsible..!