BitLocker in Windows 7, however, has significantly improved, since its implementation in Windows Vista. In Vista, BitLocker was too complicated to set up,as it requires to shrink the system partition to make space for the BitLocker partition. Microsoft acknowledged and released the BitLocker Drive Preparation Tool.
In Windows 7, BitLocker drive preperation is now integrated and greatly simplifies the encryption of a system drive. BitLocker can be found under System and Security in the Control Panel. Basically, you only have to turn on BitLocker, and the Drive Preparation Tool does the rest. This works, however, only if the computer has a TPM (Trusted Platform Module). If not, the encryption key also can be stored on a USB stick.