This is a very simple small instructional guide on how to create or make an existing folder invisible.
1) Create a new folder somewhere (I choose desktop)
2) Turn numlock on (so you can use your number pad
3) Right click on the folder, choose rename, press alt and hold it while you type 255 on your numpad, then release alt. That will get rid of the name.
4) Right click the folder again, this time go to properties > Customize > Change Icon > find the invisible icon, double click it and press ok. One of my invisible icons is five rows over, three rows down. Its a blank space, like I said, just double click it, press ok
Your folder should now be invisible =D
While this information is available at other places in the net, i wrote this guide from a blank page. I didn't copy anyone.