05 Altima wont start...HELP????

I have an 05 Altima. The SES light came on and the code was for the crank sensor. I did ignore it for a while. The car eventually became hard to start and one day would not start at all. I replaced the crank sensor along with the camshaft sensor. Still no start - Car feels like it ran out of gas (there is plenty of gas in the tank). Someone told me maybe their was no spark, so all 4 spark plugs have been changed. I was then told the fuel pump. (that was just replaced in March) however just incase i replaced it once again. The car wants to start - just still feels like it has run out of gas. I did some research and the key was a suggested problem. What i had read said that maybe it needed to reprogram the key. I tried my other key and no luck. I am at a loss of what to try next...this has been going on for 2 weeks and im going nuts...please help ___ Thanks Nicole :banghead: