1996 Chevrolet Silverado Won't Start.....

I have a 1996 Vortex Chevrolet Silverado C1500 ext cab (my first chevrolet). I bought it about 3 months ago and I had it all checked out and replaced the fuel pump, alternator and battery. It has been running great. Thursday morning, I went to work as usual and I had to run an errand about 2 hours later but the truck wouldn't start. It would turn over, but it wouldn't start. Someone mentioned that it might be the pickup coil (because it sounds like it's not getting fuel and you can't hear the fuel pump) that's in the distributor so I replaced that and it still wouldn't start. Friday morning, I got a ride to work and tried to start it and it started. I drove it around for a little bit but when I went to go home, it wouldn't start. I checked the oil and added a quart and let it sit a little while and tried to start it again, but to no avail. Could someone please help me with this problem and offer some suggestions????? Thank you Chad's wife, Kelli