HELP! car wont start
 

ok heres the story, earlier at the pizza joint i went out to go home and it would jsut sit there and turn over and over and then after a minute it finally struggled to life, so i cam home rotated my tires changed the oil and wen tot crank it up and it is doing the same thing jsut turning over, but now wont even start, what could it be? after it cranked up earlier it seemed to run fine, please any help will be greatly appreciated, scott