The gvim program alone does not have syntax highlighting enabled by default. Syntax highlighting is only enabled by explicitly enabling it with a command such as
:syntax on. So the only way to have syntax enabled is to enable it yourself at the Vim command line or to have such a command in a configuration file that's read on startup.
Vim is typically installed on Windows with a standard set of configuration commands in
C:\Program Files\Vim\_vimrc. That standard set includes
syntax on. Without any other configuration files, gvim will read that file on startup and you will have syntax highlighting.
:help _vimrc it says, "Four places are searched for initializations. The first that exists is used, the others are ignored." The list of user vimrc files includes
$HOME/_vimrc followed by
$VIM/_vimrc. On your system, $VIM is
So, when you use a
C:\Documents and Settings\myUsername\_vimrc file, gvim reads that file and skips
C:\Program Files\Vim\_vimrc. If your _vimrc does not contain
syntax on you will not get syntax highlighting.
If your are going to use your own _vimrc, then make sure you copy into it from
C:\Program Files\Vim\_vimrc any of those configuration commands you need, including