sean and ryukkid are right, the fuel filter could be clogged. What I have seen happen is that the car will start fine, then die. When you go to restart it, the dirty filter could be passing just enough fuel to get it to start but then die. Try the simple things like that first. The filter is right on the firewall and not too expensive to replace, and even if its not the filter, its always a good idea to do it because something as simple as that can give you a huge headache. Check the air filter too and if its filthy try running it without it like was mentioned. Let us know what you find.