Try creating a folder named "CON"(without the quotes) anywhere on your hard disk and i am sure you wont be able to do so.
Huh ... Now What ? Error Message ?
Because Windows Reserved Some Name like PRN , AUX , NUL , LPT1 , COM1 , CON etc ...
Here is the Solution:
Just copy from here "СON" (Without the Quotes) and now paste it in your Folder or File name .Yes the Magic Happen. But The Question is How ?? O_o
There is nothing strange in this... one of your "CON" contains a Unicode character for"C" having 1057 as Character Code. Whereas the Other "C" has 67 as Character Code. Since windows works on ASCII Characters it allows the users to create CON Folder where "C" has 1057 as Character Code.
Mystery is now solved '_'