I moved all my hard discs (x4) to the promise / Maxtor controller as I can get UDMA 133 to work -- faster than the Ide channels on the motherboard.
I have 3 DVD writers on the IDE channels on the mother board.
If you are installing Windows XP from scratch the discs WILL boot -- but on Windows install press F6 when it says Load external SCSI (I know it's not SCSI but do it anyway). Windows install will prompt you to insert a floppy disc. Windows will copy the driver and install.
If you don't do this Windows install will crap out with Error -- Cannot detect any Hard disks on your system.
If you don't want to re- install Windows -- ensure you don't connect your Boot disk to the PCI card until you've loaded the driver. So install the card, update the driver and THEN change the connections.
If you haven't done this correctly and you have no hard disks on IDE0 / IDE1 on the motherboard Windows boot will give you the famous BSOD.
Afterwards Windows will boot from any disc connected to the PCI card
In general especially with DVD authoring try not to mix DVD writers and hard disks on the same IDE channel.