Basically, a “ghost folder” is a folder that you can’t see. It’s not hidden by Windows, you just can’t see it. How, you ask? Simple.
1. Right click the folder that you want to hide.
2. Click Properties.
3. Click Customize.
4. Click Change Icon.
5. Click the arrow pointing right about 6 or 7 times, until 3 blank spots appear.
6. Select whichever blank spot you want.
7. Click OK.
8. Click OK.
9. Right click the folder.
10. Click Rename.
11. Type ALT + 255.
12. Press Enter.
13. OMG where did it go!?
There you have it. It’s as simple as that. Finally, an easier way to hide my TOP SECRET CIA files.
*Note* It works both on XP and Vista.
Source: PC Tips Box