Ok, so I want to address this issue first. While a password is important for preventing someone from USING your computer, it really doesn’t do much good for protecting the data on the computer. Yes, you can password protect your data (using Windows), but that’s risky also. While it might stop someone from booting into the computer and opening a file, it doesn’t stop them from seeing that the file exists. And if you reset your password, there’s a good chance that you won’t be able to open the file either.
If you just rely on the fact that you have a password on your login, that’s not going to do you any good. Case in point: I have a triple-boot system (Windows XP, Ubuntu 13.04, and Fedora 19) on one computer, and a triple-boot system (Windows Vista, Ubuntu 13.04, and Fedora 19) on another. On either system, I can boot into one of the Linux operating systems and open/view/run any file on the Windows drive. They don’t necessarily have the same passwords or usernames (if there’s a password at all). So, it doesn’t matter.
In fact, if someone asks me to fix their computer, the first thing I do is create an image of it. The second thing I do is boot a LiveCD and copy all of their documents, pictures, music, and whatever else they want to keep to a USB drive. Then I either fix or wipe and reinstall the computer for them. Finally, I put all of their stuff back on the computer for them. Up until I actually start to work on the computer, I don’t even need to know their passwords. ****I should note that after I’ve completed the work and verified that everything is right, I delete the images and backups. I use the images and backups in case something goes horribly wrong. I can restore them, and start over from scratch.
The point to this article is that if you’re worried about your privacy (or are required by law to ensure the privacy of your data), you need some form of encryption software installed on the computer.
By no means, am I denying the necessity or values of using a password to prevent unauthorized access to your computer. It’s imperative for logging into and using the system.