You need to install the drivers, you should of got a driver floppy disk with the motherboard, if not download them, and put them onto a bootable floppy.
When in windows setup (the first stage with the blue screen) at the bottom it will tell you to press F6 to install 3rd party scsi drivers, press F6 sometime on that screen. At the end of that it will give you the option to install the SATA drivers.