If you are getin gas an fire but still wont start why?

Don't know what your vehicle is but if it is fuel injected, it may have some fuel pressure but if it doesn't have the required amount of fuel pressure it isn't going to start. Do a fuel pressure test, you may have a bad fuel pump or bad fuel pressure regulator. Also check all the fuses. Also check the timing belt if it has one, it may have jumped or broke.