I'm assuming this is not a recent "shop build" then? Best scenario—email me

Please reply with the FCC # on the Motherboard, make/model of power supply, edition of XP Pro O/S,  it seems a confusion of terms may exist.

 Although I can with this limited info assert that the computer is classified as a 64bit machine but may not have a 64bit operating system not knowing what XP Pro edition is being used.

Just curious why you switched SATA connections?? reinstall the drivers for the HDD you will find these at Seagate website. Please describe the method used to *clone the HDD??