Some folders that cant be created in windows..

Try to create a folder in Windows with either of these names--

"con" or "nul" or "Aux" or "Lpt1".
Windows will not let you create ....
This is because these refer 2 some well known ports....
-con corresponds to the console
-Lpt1 corresponds to printer and so on....

well that is common but what about this ? Try these more

CON, PRN, AUX, CLOCK$, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, and LPT9.