You have a SATA hard drive and a non-native SATA controller. Thus, Windows requires drivers for the SATA controller before it can see your hard drive. You need to boot off the Windows XP install CD (as you were probably doing before) and press F6 when prompted (to install drivers for IDE/SCSI controllers). Then use the floppy disk when asked for the drivers later.
NOTE: make sure the hard drive is plugged into the VIA SATA controller. Your board may have 2 controllers - a VIA one and a Promise or Silicon Image one, each capable of supporting 2 drives.