I sort of lost the jumper cable in my SATA drive, and for some reason the drive isn't showing up during startup anymore. That doesn't make sense.
You'll have to find the jumper or get another one. The motherboard may have come with a spare. (The western digital jumper is white. The asus motherboard ones are blue. The color doesn't matter.)
I fully believe that this HDD is defective. After connecting it both ways (One through IDE via an adapter, and directly to my sata port) both Western Digital Diagnostic tests have failed immediatly on a cable error. I am sending it back. I'll be back if (more like when) I have any more problems.