07 XK smart key.
My car battery went dead.
Then the smart key would not work.
Replaced the key battery, still no go.
What needs to happen to get this fixed?
Thoughts?

 

It is possible the systems did not reset cleanly when the new car battery was connected (you said you had replaced it in your other post). It might resolve on its own after a few minutes to a couple of hours. If not, disconnect, the negative cable of the battery for a minute or so and reconnect it. Then try to start again after 5 minutes.

 

Stick the Smart Key in the Smart Key Port inside the center console. The port is there specifically for this problem.