My 02 fiat punto sporting won't start and the key code light on. ?

I previously had problems with my punto, the engine management light had been flashing and it was loosing power when driving, then one day just wouldn't start so fitted new ht leads and a new coil and was running lovely for a week or so then i had a few problems trying to start it, one day it wouldn't start then in the evening i tried and it was fine also every morning i tried to start it, it was struggling, but now it won't start altogether it will turn over just not start and the key code light is on. can anyone give me any suggestions what the problem could be or how i could start it? thanks