Alright, have you ever wanted to make a invisible folder, that can only be accessed if you know where to find it! Well then your in the right place! This is a fairly simple task, just have to make sure you don't loose the folder(You'll know what I mean in a minute).
Ok, so just go to the good 'ol Windows Desktop.
Create a new folder.
For the folder name, we are going to use an ALT code. Since Windows does not allow you to make folders or any file of that matter with just a space as the name, we are going to use the ALT code for a space! And yes, this works!
When you are typing the folder's new name, type this in(Make sure your NUM-Lock is on!) ALT 255(On the Number Pad).
Make sure to be holding the ALT key with typing the number on the number pad!! Release the ALT key, and you should see this:

If you see this, then all should be A-Ok! If you don't, then retry it, this should work, all the times I have done it, it worked!
Now, Once the folder name is set to basically nothing

, We need to get rid of that ugly little icon!!
To do so, right click on the newly created folder, and click Properties.
You should see a tab that says 'Customize', Click on that!

Now at the bottom you should see a button that says 'Change Icon', Click that!
A Window should pop-up with a lot of different icons (Make sure you are looking for icons in this file: '%SystemRoot%\system32\SHELL32.dll').
Scroll to the right a bit (About 9 clicks on the scroll bar right arrow). You should see like 4 blank spaces. These would be the icons that we will be using!
Choose a blank one, they are all basically the same.

Now, Click OK, Then Apply and OK on the other window.
You should now see something like this:

BAM! You know have a invisible folder! Put what ever you please in there! (To open it just select it, and press Enter).
Just be sure not to loose it.
NOTE:
If you are in CMD (Command Prompt), you have to type the FULL PATH to change directory to that folder!