Chapter 2 (c3) - ANSI.SYS will reset your Startup Menu Colors.  

If your CONFIG.SYS file contains multiple configurations, you can use the menucolor command to 
specify the color of the MS-DOS 6 startup menu. However, if your CONFIG.SYS file also loads the 
ANSI.SYS device driver, ANSI.SYS will reset your display to the default colors when it loads.
This occurs because ANSI.SYS is a block device for the console (CON). ANSI.SYS takes over all 
output to the console and manipulates the data in an ANSI (American National Standards Institute) 
format. ANSI.SYS resets the menu colors because it does not detect the previous state of the CON 
device.

 