1996 Volvo 940 starting problems

My Volvo will act like it is out of gas, it is pretty low, we put two gallons in the car and drove it home about a mile and parked it for the night. It started fine and drove to work. This afternoon, it had the same problem but adding gas did not work. It started ran for a few seconds and then died. Wen we tried to turn it over again it tried to crank but would not start up.