If your car isn't starting, one possible cause could be a blown fuel pump relay. Here's how you can check to see if your fuel pump relay is indeed the culprit.
First, check to see if there is power going to the fuel pump. If there is no power, then the issue is almost certainly with the fuel pump relay. You can check this by using a multimeter to test for continuity between the two terminals on the bottom of the relay. If there is no continuity, then the relay needs to be replaced.
If there is power going to the fuel pump, then you'll need to do some more diagnostics to figure out whether it's the fuel pump itself or something else that's causing the problem.