If you're sharing a computer and you might don't want them to share's common files or private document's without them knowing that you have another operating system hidden in the computer. Truecyrpt allows you to hide a operating system in a partition.
Truecyrpt allows you to create another partion under NTFS x2.1 or Fat32 (4Gb) of storage on hard drive. Partition the hard drive and open truecrypt. Select option system on truecrypt select creates hidden operating system. Follow on screen instruction of truecrypt.
Watch the video from Cnet that shows how it's done with truecrypt.org
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