Following are reserved names, which cannot be assigned to a file or folder (normally) in Microsoft Windows XP.
AUX
CON
COM1
COM2
COM3
COM4
COM5
COM6
COM7
COM8
COM9
LPT1
LPT2
LPT3
LPT4
LPT5
LPT6
LPT7
LPT8
LPT9
NUL
PRN
Please try it!
Vikas Khera 