Why won't my SATA hard drive work?

I'm trying to add a second hard drive for some extra room, not booting windows from it or anything. SATA and power cables in fine, BIOS auto recognises correctly, vista disk manager recognises it fine but it won't format and Western Digital diagnostics tool says "Cable test:: Read diagnostics sector error". I've tried a few different cables and power cables and all my SATA ports with my existing work-a-day drive and its fine and dandy. I keep sending these Western Digital drives (1.5Tb Caviar Green) back and the retailer has sent out the same model with the same problem numerous times. Am I doing something wrong? Is there anything I can do differently?