I've been searching for the PC version of K240 for years now and still no luck.. but... I've found a game called "Fragile Allegiance", it's a sequel (or a remake) of K240 for PC, from Gremlin itself.
It adds better gfx and sfx, biological weapons, new aliens (You can play against up to 6 aliens at the SAME TIME.), diseases, epidemies, a market much like Elite (You can buy stuff and sell for profit), black market (for illegal goods and weapons), and there's a lot in the diplomacy side (Like making treats and allies).
VERY recommended (Even more if, like me, you think K240 is the best strategy game ever done), you can get it at
(search for K240 and you will find it)