2011 Chevy Malibu 2.4L 4 cylinder with flex fuel option. All of a sudden it won't start will try to but won't crank over all the way ??

Test either with a fuel pressure gauge or test the fuel pump circuit with a voltmeter/ohmmeter.

You said "it won't start will try to but won't crank over all the way ??" There is a big difference between TURNS OVER BUT WILL NOT START and WILL NOT CRANK. Which one is it? Turns but will not start could be a sensor, security issue, lack of spark, lack of fuel, lack of fuel pressure... Will not crank could be a starter, battery, connection, relay.... it's very hard to try and help with so little to go on. May require testing to pinpoint the cause of the problem.