OK so this is a guide on how to make a truly hidden folder. This is for windows XP.
This folder can be used to hide your secret porn stash

or anything else you want to hide from others

.
First make a new folder in a place where you wont forget about the folder.
For example I will place it on my desktop.
Now right click the new folder and choose rename. Hold the ALt key and type 255 and hit enter. Now you can seee there is no text under your icon.IF in case your computer writes *,there is another way to do this.Go to Start > All Programs > Accessories > System Tools > Character Map.When you open character map,you should see a blank field,just white,that means it's an invisible icon.Here it is.

See topic
No Text Under Your Icons
Ok now lets continue, right click the folder again and choose properties. Then go to Customize and at the bottom change icon. Now scroll until you get to these 3 icons.
Choose 1 of them and press OK and there you go you now have a secret folder.
You can watch this on video that I made.
Video Link
If in any case you want to make it even more secure,and lock it,just follow
Diesel's Guide on how to lock folders
The video link has been added. Enjoy