Burning smell, won't start now

The information provided is insufficient for us to understand the problem so you would have to explain in more details. Presently we can only guess what could be wrong and it is not going to be accurate.

When the burning smell occurred, did any indicator lights turn on?
When ignition is turned on, do the dash lights turn on and are they bright?
You mentioned the battery sems to be flat, that would indicate a charging fault, most likely the alternator is not working correctly due to a seized bearing or bad harmonic damper as you had burning smell, which could be the belts slipping. Was there any unsual/abnorn]mal screeching noises?