That protocol is defined in your bios. There is a place in our bios to define to boot protocal for yor SATA drives. Initially, It might be easier just to take out the slave for now and install windows on the 10k WD drive. You need your XP cd. Go into the bios and in the boot priority section, You make your first boot device the cdrom, then the hd and floppy. You bios will then boot to the cd and you will be prompted to hit any key to boot from cd and you will then enter XP setup. Once in setup it will find traces of the originally installed OS and then choose the one that does not keep the current file system intact and then do the format (not the quick). Let us know what happens.