Volkswagen 2001 new beetle issue?

i just recently bought a used beetle (limited isotope green) for only $2500! yes, it was a bargain. anyway, i spent $700 to change the old parts in order to p safety. then, i spent another $700 to change its catalytic converter for emissions test. for me, that's fine since i love the car so much! now i have an issue again where the car just randomly won't start! it just happened a few days ago. when this incident happens to me, i just simply put it on neutral and press on the gas while starting, then it starts fine. but what could be wrong with it now? anyone else have the same problem? help?