How often have you wanted to hide a drive from users you know will look around and mess something up? Well, here is what you do.

You can have a drive not show up in the My computer using this simple Registry edit.

In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer

Name = NoDrives

Type: REG_DWORD

Value: To calculate the value, add together the numbers for the drives you want to hide, using the formula: A=1, B=2, C=4, D=8, E=16, F=32, G=64, and so forth. To hide D: & E:, the value would be 8+16=24.

Thats it.

Source here