Contour won't start

I left my 1999 four cyl Ford Contour parked for several weeks. Now it won't start. Thinking that the trouble could've been caused by a faulty battery, I
purchased a brand new one. But still it won't start. The engine cranks but doesn't start. I know that the problem is fuel related and not electrical because when I spray starting fluid into the air intake it does start for about 3 seconds. I changed the fuel filter but nothing. Somebody told me to try to keep the accelerator pedal depressed while cranking the engine. Today I tried that and the engine did start and ran for about 15 seconds, but then it died. When turning the ignition key on I can hear the fuel pump for about 2-3 seconds. The car ran very well until I parked it for about 5 weeks. Does anybody have a clue about what the problem may be and what I should check next? Many thanks in advance
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.