BIOS Boot Order Disabled

I have an Inspiron 9100 BIOS Version A06.

I'm triyng to change the Boot order of my BIOS, however when I enter the BIOS and go to the section that has Boot Order there is a highlighted line with "Configiure Setup is Disabled". I can't move up or down on the boot order.

Does anyone know why this is disabled and how to enable it?

I got half way through a clean WIN XP install and had issues, so now I want to start again with just booting off the CD, however that is last on the boot order so need to change it. 

PLEASE HELP