How To Hide a harddisk partition in Windows Xp/Vista

You may need to hide a drive either for security reasons (to ensure that children do not have access to a backup drive, for example) or for practical reasons (if your PC has multiple memory card readers never used).

Here’s how to do so, under XP and Vista.

A command in the registry will tell Windows Explorer not to display some readers.

Technically, the system uses a binary value of 32 bits where each bit corresponds to a reader. Bit 0 is the drive A, bit 1 in drive B, etc.. When this bit is “1″ the player is hidden, otherwise it is visible.

Go to Start, then Run and then type regedit.
Deploy the “HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Policies/Explorer”
If the DWORD (32 bit) named NoDrives does not exist, start by creating (click the right mouse button and select New then Value DWORD).
Double-click NoDrives to amend this item, select Base Decimal and enter into the data field the decimal value of the player to hide (e.g. 512 for the drive J: )
If you hide multiple drives, take their different decimal values and add them.