Well, Try to create a folder in windows platform with the name CON, AUX, COM1, COM2, COM3, COM4, LPT1, LPT2, LPT3, PRN, NUL....

You cant able to do it...
Its just because of some system calls of this services already been there for those names. So If you try to create or delete those system calls, It will restrict you in doing them... But I have a solution to this..
Try the following steps.. :

STEP1: goto command prompt

STEP2: type in prompt c:\> "md \\.\c:\con"

STEP3: verify by typing "dir \\.\c:\con"

STEP4: delete the file or folder "rd \\.\c:\con"
Now you can see a folder named con in your c drive... Give replies...