Well,

What exactly are you trying to protect?

If you are using a shared computer, where others have physical access and it runs a Windows home operating system you cannot protect anything, period. You would be totally reliant on other people's ignorance.

The only thing you might do to protect your work from "the ravages of siblings".....(sticky fingered brothers and sisters ) is to look at a product called "Scramdisk" This creates a virtual hidden drive that is encrypted and protected by up to four passwords. You "mount" the virtual drive then use it just as normal. I use this system to maintain a mirror of my C:\ for backup purposes.

If, as I suspect, your concerns are sticky fingered brothers and sisters this should work, but you should also consider physical back up of your data...........they may trash the whole machine? and it is getting a bit old, is it not?

I would NOT go for file compression.............I have had bad experiences with it, where the compression manager file became corrupted when the HDD crashed

However, due to your environment, you are not able to protect yourself from anything other than "accidents"

Physical ownership = total ownership, believe me!

Good luck