With this simply yet wonderful registry-tweak you will be able to hide your drives.
1) Go to start–>Run.. and type regedit
which opens the registry editor window
2) From the left side pane of it browse the following path
HKEY_CURRENT_USER -> software -> microsoft -> windows -> current version -> policies -> explorer
3) Now in the right pane create a new DWORD item and name it as “NoDrives” (without quotes and its case sensitive) and modify its value and set it to
3FFFFFF (Hexa)
4) Restart computer and its done.
NOTE:: To again display the drives simply delete the DWORD we created and restart.
( always be careful while working with registry, don’t overdo anything you aren’t sure about)