How to Hide and Lock Hard Disk Drives in "My Computer"

follow this intructions :

1
Click on the "Start" button. Go to "Run", type "gpedit.msc" and press enter.
2
Wait for the "Group Policy" window to appear. Click on the "+" button beside User Configuration then click on the "+" button beside "Administrative Templates". Then click the "+" button beside "Windows Components" and then click "Windows Explorer".
3
Search for "Hide these specified drives in My Computer" in the options that appear in the right column of the window. Double click it, enable it and choose the drive(s) you want to hide.
4
Search for "Prevent access to drives from My Computer". Double click it and repeat the previous step if you want to stop accessing any drive by "command" (e.g, by typing "C:" in the address bar or "Run").
5
Close the group policy window.
6
Restart your computer for changes to take effect.

only first hardisk drives can be locked here

Warnings
If you are using the "Hide these specific drives in My Computer" option, your hard disk drives are still accessible by typing the Drive Letter in address bar or "Run".
Any user of the computer with Administrative Rights can change these settings. Realize your disk drives are not as secure as originally thought. If you apply the prevent access, however, then nobody can access the drive.