if its the 8790, you must connect a usb external floppy drive first, then when you boot with the windows xp cd, when it asks you to hit F6 for adding raid or scsi drivers, hit F6. then put the floppy with the raid drivers for the 8790 in and let it find them and install them, then it will find the raid controller, once it finds the raid controller, it will then see your hard drives.