Was it running and stopped or just wouldn't start one day? Based on what you have said I would open the fuel line going to the first filter and make sure it is flowing from the tank. If so, check the manual fuel pump by opening the bleeder on the injector pump and manually pump the lever on the manual fuel pump to see if it pumps fuel out the bleeder. If it does then continue to pump till you get the bubbles out and then close the bleeder and try again.
I have found mine start much easier after running out of fuel by opening the actual high pressure line/lines coming out of the injector pump. I usually will just crack one of them open and then spin it over till it starts to hit and then close it quickly. These high pressure injector lines will need to be really tight.
Good luck.