WD tend to include legacy bits in their drives (like the old molex power connector). Jumpers aren't necessary for SATA drives though, since there's only one per cable!
I got courious as to why they would put jumpers on if they weren't needed.I found this on the WD website.
Set the jumpers:
The drive has a jumper block located next to the ATA power connector. There is generally no need to change the default jumper setting in order to use the drive. The only use of this jumper block is to enable or disable power management for the drive. The drives ship in the default position with the shunt on pins 1-2 (disabled). Alternately, the jumper can be removed completely with the same result. Placing the shunt on pins 3-4 (enabled), designates that the drive will power-up in standby mode. For most users the default position should be used.
I aslo found this , I hope it helps you unionman.
I know you werent installing windows at the time. Thought maybe it was related somehow.
Problem:
The Windows setup process does not detect any hard drive when you try to install Windows 2000 or XP onto a Serial ATA hard drive.
Cause:
The Windows 2000 or XP CD does not currently contain the drivers for Serial ATA controllers.
Solution:
When starting the Windows installation process, watch the bottom of the screen for a prompt that asks you to press the F6 button to install SCSI or RAID drivers. At this point you should press F6 and install a floppy disk containing the drivers for the Serial ATA controller on your motherboard. You can also have the drive attached to a Serial ATA controller card and use the same process. The Windows installation process will install the drivers for your Serial ATA controller and recognize the hard drive so it can finish the system installation process.