No light on unit

I have received my reader and have loaded the program when it asks to plug in unit to computer and then reset computer it gives me a message saying no power to unit the message comes up in the window we’re you choose English.
 

It's powered by the car

I know that but the instructions says plug in unit to computer you do not need to connect to car it’s so computer can recognise the unit that’s when it says unit has no power and will not do the next step

Mine did the same until i plugged it into the car

if it says that the unit has no power then you must have just completed step 7 of the instructions.

Please proceed to step 8 which says:-

"Plug the interface into your car and into your computer.Make sure that the interface has a green flashing light."

I was staring to think this might be needed thanks