If your phone is not turning on by the conventional way of holding the button on the back of the device, there may be a problem with your battery. Try removing the back of your device and taking out the battery and after 10 seconds putting it back in. Usually that soft resets the device and has potential of making it work again. If any more questions or concerns please refer to the LG G Stylo Troubleshooting page

There can be lots of underlying problems when it comes to your phone and memory issues. Common way to fix issues with your phone running slowly is by clearing running apps or programs that you are not using but are still using memory. To clear your phone's apps you go to the home screen then click Apps. Tap Settings then go to the general tab. Scroll down to Phone Management, then tap Apps. Once there you can swipe left on the screen to view the running processes on your device. There you can stop desired apps or programs that are taking up extra memory. If any more questions or concerns please refer to the LG G Stylo Troubleshooting page