either 1 you plugged in the power cable wrong and killed the drive or 2 you have bad flashed it.
you will need another (SATA) device that will register in mtkflash to try the bad flash recovery, another working samsung is best but you can most likely use a sata PC drive or the 360 hard drive.
after getting the other drive registered (with a write command) power it off and disconnect it, connect the samsung in its place, make your selection and power it on, if it doesnt start writing then you need a new drive board or drive.