r reg nissan micra won't start?

I have a 1998 1.0l nissan micra and it wont start in the morning. once it is started it will run for the whole day but leave it over night and the next morning i have the same problem. sometimes it starts if i remove the fuse that sends the petrol to the engine but recently this hasnt been working and the battery keeps dying. my mechanic friend took the spark plugs out and theyre soaked with petrol suggesting there's too much petrol getting there. ive changed the spark plugs, got the sensor that is supposed to stop too much petrol getting to the engine and also replaced the part that measures the engine temp (i think, i didnt do this myself!) but i dont know what else to do! ive already spent so much money on it changing different parts. can someone please heeelp!