Re: please help
A/C uses 110 volts AC, so in order to run the A/C in the unit, you need either to have the generator running, or be plugged into an AC outlet. I'd suggest you do plug in if practical, as this will allow you to check out the A/C operation independant of any problems with the generator.
Reasons the generator won't start:
1) Problem in the wiring harness (disconnected, corroded, 'eaten', blown fuse or just 'shut off')
2) No/inadequate power from battery (bad, not charged)
3) Generator low on oil or low oil switch defective
4) Generator or starter 'frozen'
There are many other things which can go wrong with generators, but with them at least you should hear it crank, so I'd start with these. Probably the first step would be to change the oil, and the next would be to use a voltmeter to make sure the unit is getting control and cranking power.