to see if the SATA ports are actually active and marked to be bootable? This would be an ATA configuration rather than a RAID, so use your mobo manual to make sure the original configuration that made it work the first time around stayed the same after the flash of the new bios.

During the reinstall of XP, did you press the F6 key immediately when at the first page or so of the 'setup' in order to let XP know that you have SCSI drivers (actually that's how your SATA drivers get installed so don't be confused just because it says SCSI)? Those drivers will be installed later in the setup.

TONI