Protecao de HDD por password

[pauloca]

Olá a todos.
Tenho um HDD externo de 250 GB com 2 particões. Quero proteger 1 delas com password mas a que possa ter acesso em qualquer computador a que o ligue (tipo a pass estar no HDD e não no computador). Podem por favor indicar-me um programa (de preferencia free) ou uma maneira de fazer isso.

Win XP Pro
Pentium 4 3Ghz
Asus P4P800 Deluxe
GForce FX 5600

[LuisFilipe]

O sistema NTFS faz isso nativo e como o XP usa esse sistema e 'acho' que tem ferramentas para o utilizar basta por a bombar.

Agora como... bem com uma procura acho que será linear encontrar uma referencia ou mesmo um guia.

Googla, Wika...

EDIT:
http://en.wikipedia.org/wiki/NTFS#Features

Encrypting File System (EFS)
EFS provides strong and user-transparent encryption of any file or folder on an NTFS volume. EFS works in conjunction with the EFS service, Microsoft's CryptoAPI and the EFS File System Run-Time Library (FSRTL). As of February 2004, its encryption has not been compromised.
EFS works by encrypting a file with a bulk symmetric key (also known as the File Encryption Key, or FEK), which is used because it takes a relatively smaller amount of time to encrypt and decrypt large amounts of data than if an asymmetric key cipher is used. The symmetric key that is used to encrypt the file is then encrypted with a public key that is associated with the user who encrypted the file, and this encrypted data is stored in an alternate data stream of the encrypted file. To decrypt the file, the file system uses the private key of the user to decrypt the symmetric key that is stored in the file header. It then uses the symmetric key to decrypt the file. Because this is done at the file system level, it is transparent to the user. [11] Also, in case of a user losing access to their key, support for recovery agents that can unencrypt files has been built in to the EFS system.

http://en.wikipedia.org/wiki/Encrypting_File_System
Disk encryption software http://en.wikipedia.org/wiki/Disk_encryption_software
TrueCrypt (open-source, free) http://en.wikipedia.org/wiki/TrueCrypt

etc, etc, etc...