If nothing else has worked to help your screen, you can follow this step by step video to help you replace the screen. https://www.youtube.com/watch?v=74P614un... You can find new screens by Googling “Samsung Chromebook 2 screen”. Check out the troubleshooting page for further help.
Press Esc+Refresh+Power and follow the instructions on the “Chrome OS is missing...” screen. It will prompt you to create a Chrome OS recovery media, which can be created by the app “Chromebook recovery utility” from the chrome web store.Check out the troubleshooting page for further help.
Unfortunately the battery sometimes is faulty and replacement is the best course of action. You can follow this guide to replace your battery. https://www.youtube.com/watch?v=RfTQBYcf... For further help you can also check out the troubleshooting page.