Hide Computer Drives

This is yet another trick you can play on your geek friend. To disable the display of local or networked drives when you click My Computer go to :
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
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.

adopted from:majid hussain