> As I understand it, Miranda established that the 5th amendment applies to all interactions with law enforcement, not just answering questions in court. So they can search the hard drive all they want, but the constitution protects us from being required to disclose what's in our heads which, in this case, should include the password.

The privilege against self-incrimination applies to any interaction which they introduce into evidence against you in a criminal case, or from which they derive information on which they then gather other evidence that is used against you in a criminal case.

It doesn't actually protect you against the police doing anything, or forcing you to provide information (other Constitutional provisions may, however), it just protects you against certain information being used against you in criminal court.