I have not yet bought Minecraft because I have to first check if it works on my PC, but it is not working. The Demo_World fails to generate. Please check the attached pictures in which I have shown the game output and the launcher log.

Game Output:
[08:43:35] [Client thread/INFO]: Setting user: Player
[08:43:35] [Client thread/INFO]: (Session ID is token:50e79e5c2c94446db3aa8cb546c92cde:00000000-0000-0000-0000-000000000000)
[08:43:38] [Client thread/INFO]: LWJGL Version: 2.9.4
[08:43:39] [Client thread/INFO]: Reloading ResourceManager: Default
[08:43:39] [Sound Library Loader/INFO]: Starting up SoundSystem...
[08:43:40] [Thread-5/INFO]: Initializing LWJGL OpenAL
[08:43:40] [Thread-5/INFO]: (The LWJGL binding of OpenAL. For more information, see http://www.lwjgl.org)
[08:43:40] [Thread-5/INFO]: OpenAL initialized.
[08:43:40] [Sound Library Loader/INFO]: Sound engine started
[08:43:41] [Client thread/INFO]: Created: 1024x512 textures-atlas
[08:44:45] [Server thread/INFO]: Starting integrated minecraft server version 1.9
[08:44:45] [Server thread/INFO]: Generating keypair
[08:44:46] [Server thread/INFO]: Preparing start region for level 0
[08:44:47] [Server thread/INFO]: Preparing spawn area: 0%
[08:44:48] [Server thread/INFO]: Preparing spawn area: 17%
[08:44:49] [Server thread/INFO]: Preparing spawn area: 36%
[08:44:50] [Server thread/INFO]: Preparing spawn area: 58%
[08:44:51] [Server thread/INFO]: Preparing spawn area: 84%
[08:44:52] [Server thread/INFO]: Changing view distance to 8, from 10
[08:45:39] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 2248ms behind, skipping 44 tick(s)