Used this guide to replace a home button on my iPhone 4 which stopped working after the iPhone was out in the rain for 30 minutes. Worked like a charm. It was very hard but I took my time. Unfortunately, it didn't fix my problem. Upon further research, the dock connector was the culprit. It is where the home button plugs into. Replaced that using a guide here and now everything works great. So if your home button doesn't work after replacing the physical button, try replacing the dock connector.