Mobs not spawning

I've been having this issue for a long time (like, over the past several years), but any time I start a new game mobs do not spawn in any world, no matter how I configure them. I can sometimes get things like tallbirds to spawn in certain biomes only, but otherwise there's nothing. I've tried uninstalling and re-installing, not using mods, and so on, but there's still nothing and I have to use cheats to add anything which has gotten a bit old. I'm not particularly techy so I don't know what you'd need from me for this but just let me know. Thanks! 

DxDiag.txt log.txt