I have a 2003 X-type 2.5 manual transmission, and early November, my wife lost the second key (first one was lost soon after we bought it new) The dealer wanted around $900 for a new key and programing, plus the cost of towing it out to their shop, but I recently found a mobile service that cut me a new key with a new chip sensor for $500. It's just a basic key with no other buttons for locking etc. It seems alright, it lights up the light on the console and turns the engine over, but the motor won't start.
One thing i suspect is the gas. It had a full tank of gas since November but has been siting for three months. And of course the gas has ethanol in it, which goes bad.
Any ideas on what else it could be?

 

To start with, $900 (..and US$!!!- for a little bit more I bought a X-Type - without reverse gear, though...) is a massive rip off, $500 is still a very big rip off.
If the engine turns over, it really does not sound like a key issue.
Yes, ,fuel can get old, even after already 3 month. Even without ethanol mixed in there (I never use ethanol mix).
I had the problem many times before on my Ford Fairlane NL, because it has LPG (do not know, if you know in the US, what LPG is: Liquid petrol gas = liquified gas) and a second gas tank for LPG. Since LPG is cheaper, the petrol in the Fairlane does not get used and gets old, and then a new fuel pump is due. If you place a new fuel pump into the old petrol, it will also seize up immediately. Find a way to check, if your pump pumps.
Equally, if not more, likely: Dead battery!

 

Thanks for the reply Peter.
It's not a dead battery, because the starter cranks the engine for a long time

 

One thing, I have not figured out yet (as there was no need to luckily), of how to check on a car (like X-Type), if it has spark (...on the plugs), as every sparkplug has its individual coil.
I know how to do it on Ford Fairlane, with a dizzy (Australian for distributor) and ONE central ignition coil. I replaced both already twice. So on the Farilane you just remove 1 sparkplug and hold it outside of the engine against "ground" (metal of the engine / do not touch the metal of the spark plug while testing) and watch, if I can see a spark, while someone else tries to start the car...

 

There are COP (coil on plug) testers.