URGENT how can i start my renault again ???????!!!!!!!!!!!?

car just stopped now cant start it...so what happened was ;serpentine belt snapped, battery drained flat by no alternator, changed belt, then jump started it,fired straight up, no problems whilst starting, it then idled for a good minute or two, power windows would only go up in little bursts, everything else seemed fine,then it just stalled, when to hit the start button again, but motor turns over, doesnt seem to be getting spark or petrol,ive also noticed, immobiliser light flashing constantly, cant seem to turn it off, it either spins motor with firing, or starter tries to engage,(like battery is flat) click click click,but ive noticed red light constantly flashing all the time. i think its an immobiliser problem, also now windows wipers blinkers wont come on or work , lights work ect,door locks,ect working fine but cant seem to turn immobiliser off, ive only owned this car for a week so its all new to me as ive never operated a vehicle of no later then a 90model ford..........ive taken battery out charged fully,,,about to put battery back in .... is there anything i need to do .....like reset the ecu/immobiliser ect before i attempt to start it again ,,,,all suggestions will be greatly appreciated,,,,thaks