How to Lock CD Rom

You can lock your CD Rom with this easy trick.
Go to Start=> Run
And here you type " regedit " and hit Enter.
Now follow this path.

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SeCEdit\Reg Values\MACHINE/Software/Microsoft/Windows NT/CurrentVersion/Winlogon/AllocateCDRoms

Or 

In registry editor window press " Ctrl+F ".
Now another window will be open and here you type " AllocateCDRoms ".
Now on the right hand side, right click and create new DWORD entry.
Make his name " Lockcdrom " and give the value " 0 ". 
If you want to unlock, so the DWORD value change " 0 " to " 1 ".