Basically, what's going on is this: Newer motherboards have replaced the traditional BIOS with UEFI. But drives with older operating systems, and certain CD and DVD-ROMs, won't work with UEFI, only a BIOS environment. So CSM (Compatibility Support Module) emulates a BIOS environment to be backwards compatible and let those things run. Sounds like the Windows CD you're trying to boot from is one of those.
What you want to do is go into the UEFI/BIOS menu (by pressing F2, F10, DEL at startup, whichever one it is for your machine), then in one of the menus there should be an option to enable or disable CSM. It's probably under Advanced > Boot > CSM from the sound of it.
Anyway, turn that on and hopefully you will be able to boot from that disc.