Found that nobody can create a FOLDER anywhere on the Computer which can be named as "CON".
also not create this name as folder...
CON, PRN, AUX, CLOCK$, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, and LPT9 .. like this .. :(
BUT now its possible with my blog.
Step 1:
Open Command Prompt
(start > run > type cmd )
Step 2:
Now Enter this command.
md \\.\d:\con
(this will create con folder in D drive).
Now Remove this con folder
Step 3:
Enter this command.
rd \\.\d:\con
(this will remove con folder in D drive).
Enjoy :)