Cellus

First thing is first, are you trying to collect evidence upholdable in court from the drive - as in computer forensics? Please tell us exactly why you want a bit stream backup (that's what you're asking for, also known as a mirror image backup).

If it is delving into the realm of legally-upholdable evidence and computer forensics it is vital you say so before even touching the machine. The procedure for copying data from a machine for legal purposes is extremely strict and uncompromising. It's important to know beforehand. Also note if you are serious in pursuing this in a court of law. If you're doing it to, as a shameless example, to see if someone had deleted a copy of your secret family recipe for guacamole, then ignore the following below.

If it is a serious matter that you intend to pursue in a court of law, please do the following:

1) Do not shutdown or turn off the machine. Shutting down a machine changes dozens of files, including clearing your page file among many other things.

2) Contact a Data Security firm in your area immediately and see if they have experience and are certified in Computer Forensics. If they are, tell them you need a Bit Stream Backup of a hard drive for evidence and follow their instructions. This will cost money, but these people know exactly what to do and can make an evidence-grade copy of your data that can be used in court, can maintain the proper chain of custody, and so forth.

If it isn't serious, then you can find software bit stream backup programs on the internet (make sure they can block writes) or even a hardware appliance with a write blocker that does bit stream backups and do it yourself.