A. The syntax \\.\ does not work with a file named con or nul .
In fact, no Win32 tool may delete these files.
A solution is to use non-Win32 tools.
For instance, the Resource Kit contains POSIX utilities such as rm.exe, which allows to delete these files:
Note: the files may have been created with a tool such as notepad or more, using the streams notation. For instance, type "notepad con:foo" on an NTFS partition, or "more < any_file > nul:bar"
There is an easier way, without using reskit and non-native subsystems which is to rename the file then just delete:
C:\> ren \\.\c:\nul. file
C:\> del file