Sometimes hiding files do not work because many will be knowing how to unhide the files. Small kids can unhide the files because their computer teacher has thought them how to do it as it was included in their syllabus. There are alternatives like security programs in the market which cost a lot.
I have found an alternative for this. I have found out that hiding files in some unusual places (like windows directory or other dirs in ur windir etc,)can help you secure your files to some extent ('cause no one will bother to look in such places)
In some cases changing file names along with the file extensions also work.

This can be done more effectly by implementing both the above
for example a file named EAB.doc can be made as e43.dat and save it in your windows directory or by giving the extension to be dll and putting it in your root directory such as C:\ can also help because no one will bother to delete a dll file.

Now you are the only person who knows where the file is and what it opens with

Note: Do not use 'open with' to open the file instead open the program to in which you created the file and then open the file using that program. This will ensure that the system regisry will not set the file extension to automatically open with the particular program.

This method is not a very effective way but still can act as a 'first line of defence'

Yes I have done that type of thing before, you can do that with certain files that msn doesn't like you to be able send. I'm not sure why, but it doesn't let u send those html help files. You know the ones in the form of .chm (i think?). So you change the extension to .txt and the person on the other end will be able to accept it and then they just have to change the extension back to what it was originally. It works a treat.

There are, of course, other ways to hide files. It is actually possible to hide files within other files. This may sound a little bit silly, but it does work. You can do this by using Alternate Data Streams (ADS). Bear in mind that this only works (to the best of my knowledge) with NTFS file systems.

The basic idea behind ADS was for it to used as a way for storing extra data within a file. The most common use of this can be seen by right-clicking a file and going into the properties section. Here the comments and other bits that you might see have been included with ADS. One of the really cool features of this ADS is that you can use it to hide whole files within other files. To show how this works, you just need to either go to the DOS prompt or "run" from the start menu and type something like this:

type c:\file_one.txt > c:\file_two.txt:file_one.txt

Now what this does is it hides file_one.txt in file_two.txt. Ahh so this is good but how do u access file1.txt if it is hidden? Well all you have to do is type this (same as before):

notepad c:\file_two.txt:file_one.txt

And then this opens the file in notepad. This is just an example of how i use this feature, but you can hide any type of file within another file. The best thing about this is that the hidden file is undetectable to the average user, when you use DOS or explorer, the filesize shown is the size of the non-hidden file, the only thing that changes is the size on disk, not the actual shown filesize. The other thing is that you can edit the file and then save it again and it doesn't affect the file that is hosting it. So give it a go, and check up on google if you want to know more about Advanced Data Streams. I have found it to be quite useful and there are a few programs designed specifically for searching for ADS files within your computer. By the way, should this be a new topic? I guessed that this was still about hidding files so its basically the same.

Simply said, this doesn't work, but maybe i did something wrong.

In my opinion though, if you want to protect documents, it's better to encrypt them for all that matter, or even better use both encryption and ads. Since hidden things are quite much easier to find than nonhidden but encrypted things.

I would definitively say "don't put anything under c:".
This should probably take place in the "operating system" forum, but I strongly recommend that you put no personal file on the c: disk.
Once your system works correctly (let's say the first day you buy your wonrderful PC), you should do a full backup on a removable device (let's say a CD).
Then, you should write all your personal files (wordprocessor text files, your c programs and whatever you need) on a separate partition.
So, next time you will do a big mistake (yes, Murphy's law say you will do, I did too), or if you have bad luck with a virus, simply reload you backup and your system will be fine again.
And you will have lost all the things you wrote as c:\something.dll.
So, my message is : don't put anyting onthe same disk as the operating system disk.

yup, the best way to hide files is definitely encryption.
One way I used to do was using winrar.
Just using winrar, compress the file using a password. while doing it there is an option to encrypt file names a well. So without a password one cannot even open the file to c the filenames unlike winzip where filenames are visible.
Now open this .rar file in a text editor and remove the first 4 characters in the header , should be something like "Rar!". Save it to the disk.
Now rename it to some other extension. Most of the filters too would not be able to get through this.

Cheers,
Himanshu

how about this solution, Use DriveCrypt to create a virtual drive which where u hide ur files, then enable the security options that will not allow user to delete files with drivecrypt extensions (.dcr). You cuold always download drivecrypt with cracked or serials. Drivecrypt uses the AES, the latest and most secure encryption algorithm known to the world. Of course not included those used by NSA, CIA and FBI. You could even hide your virtual drive to a .wav file
what do u think?

DriveCrypt eems really great.
Of course, I see no real reason for krypting my files :
There a so many files that I forget where each one is ans what it's useful for.

Myself I just save them to a rewritable cd and lock it away. Where you want to put the cd is up to your imagnation. That way its not on your computer for someone to find by chance. Another good hiding spot is mix the cd in with all the rest of your cd's.

Other than encrytion or hiding files (as mentioned above) I find that password protecctiong files can be useful too.
Many programs (eg Microsoft Word, Excel, etc) allow you to save files with a password. For those that don't, I find adding files to a password protected .zip or .rar archive quite secure (and best of all - free!), as long as you choose a strong password and nothing easily guessable.

Usually, password protecting files is about the same thing as encryption. If you password-protect something, there are 2 ways to secure the file.

1. Put the password in the file for the program to use
2. encrypt the contents with the password and add a checksum of the original file at it.

with 1. All you need to do is read the password out. With 2, that is not possible.

Anyway, I think that nowadays encrypting something and password protecting something is about the same, both need passwords.

The reason i prefer saying encrypting is that it's not so long as password protecting

About drivecrypt, doesn't that make working slow? all that encrypting and stuff? Am I wrong if I say that with frequent used files it's more a hassle?