This is a foolproof way to manually hide your files and it works in most of versions of Windows as long as it has MS DOS. I'm not computer savvy, and some people may laugh at this, but yeah it works fine for me, especially when I have private things that I want to prevent from being seen on a shared computer.

Go to Start, Run, type cmd and press ok to run MS DOS. Then, go to whichever folder that the file/folder you want to hide is in. For example, if your file is a.txt in My Documents, type "cd C:\Documents and Settings\(Whatever name you use for your computer)\My Documents" to go to My Documents. Then, type "attrib a.txt +s +h" and poof. Your file just 'disappeared' from your computer! To make it appear again, just type "attrib a.txt -s -h" provided you already are at My Documents already in MS DOS.

If it is a folder, for example a folder named Updater in My Documents, follow the steps but when you give attribute to the folder, there is no need to type any extension (since it doesn't have any) so just type "attrib updater +s +h" to make it disappear.

The attrib command is basically giving your file or folder attribute. "s" refers to system and "h" refers to hidden. But when you add both "s" and "h", somehow it goes further than just make it hidden. You can't even see it in MS DOS itself after giving it such attribute.

The only way to know that something is being hidden in My Documents (for the example sake) is by checking the folder size and add up all the size of the other components. But even if someone realizes this, they may not be able to open the file or folder unless they know the file name. Yeah. Again, I'm not a computer savvy or a hacker so this is as far as I know. Hope this is somehow useful!