New dvd drive causes pc not to power on

Bit of an odd one, i have just purchased a LG Gh22ns50 Dvd-RW Sata drive, and once i connect the sata power cable to it my pc will not power on, clicking the external or internal power buttons does nothing, i have tried all the usual fixes, changed cables checked connections, updated the bios i eventually completely rebuilt the pc however if i connect the dvd drive the pc shuts down instantly and will not power back on till i disconnect the drive and than turn the power supply on and off.

However i can actually get the drive to work i have one of those internal hard drive readers that allows you to read hard drives via a multi adapter and then into usb, it has its own power and connects to my pc via a usb cable, if i plug the drive into this than not only does it power on but windows can read it fine. my other dvd drives are ide so i thought it might be something to do with the motherboard (Asus p6t) drivers but they seem up to date

anyone have any ideas why this is happening and a possible fix?

(my power supply is 1200w and is nowhere near capacity)

Replaced the drive with a new one from the store, same problem, however once i plugged it into a different line of sata power connectors from the power supply (the same one as the hard drives) everything works fine, it operates fine and the computer works perfectly, so i take it something is wrong with one of the power supply's sata power lead things (power supply has two long cables each with 4 sata power leads on it). I did try using various leads out of it both the end and a middle one both cause the pc to power off,

so anyone know what would cause a power supply to do this?

If available, you may want to use the PSU manufacturer's forum. You might not be the first to experience that problem with that unit.