Now you're into troubleshooting. One of the best ways to proceed is to take all components out of the case, and get a dry insulating surface to temporarily assemble parts into a basic system The technique is called "breadboarding". Basically you start with the very minimum collection of parts together and try to start it up. If it fails, you know the problem must be among that limited collection. If it works, you shut down, add one more component, and repeat. Keep it up until you fail - then you have a major suspect in the last item added.