The most likely causes for your problems are that something is wrong with the charger,charging port, battery, or it could be something wrong with the display screen making it appear to be off.
You should probably check the [[Pyrus PY21S03211 Troubleshooting|Troubleshooting Guide]] for help. It covers both of these problems. Also if it is just the screen then the [guide|63707|Display Screen Replacement Guide] could help your problem.