Soundy might be coming from either fan or speaker. It is easy to locate if noise is coming from speaker by playing music on full volume. Fan problems might be serious. Check if you have a dirty fan. Cleaning it up will solve the problem. Overheated fan could make a lot of noise too. You will need to re-put the thermal paste for fan.
It is probably a problem on the battery. Remove the battery and unplug the power cord. Plug the power cord back again to check if the screen is responding. If screen is responding in this case you will need to replace your battery with a new one.
Check all running application at background. Use Ctrl+Alt+Delete command to open task manager and see all the applications having impact on memory at the moment. Close all one by one and restart your device. If it is still not working then the enter key is broken. You could replace it or use Ctrl+M instead of enter key.