I started Minecraft and loaded into a world, everything was fine at first, but 2 minutes later I heard weird noises of Banging, I thought it was my imagination, but it wasn't... I came to investigate and found a red block in the middle of nowhere, I was confused and thought someone was messing with me but I remembered that I made a single-player world, and I didn't make it multiplayer. I was scared, so I decided to build a base and hide in there, the Base was made of wood and stone, I then found a sheep and decided to kill it, but the sheep disappeared after I looked at it, I thought it was an error from the game, so I hunted for more sheep, I discovered this sheep with red wool, I decided to kill it with my sword, which I did. but then I noticed something was in the chatbox, I thought I made a single-player world, so how could someone message me in that world? the message said, "YOU MADE A HUGE MISTAKE..." I was confused and said, "who are you?" the unknown person replied saying "I HATE YOU!" I then responded with "what are you talking about?" the unknown user was called Red909 after I sent that message he never responded back. I was shivering... a lot so I decided to leave the world after I left my computer shut down, I thought it was updating or something so I pressed the start button and it worked, but my wallpaper changed to Solid Red, I was confused and restarted my computer, instead of saying "restarting" it said "Too Late..." I was scared so then I decided to start my computer again, and it worked. so immediately I went to the forums and said "does know who red909 is?" a few minutes later someone responded saying "STOP" the person was called Redman134 I replied to his message and said, "what are you talking about?" he then never responded so I decided to Delete Minecraft and never use it again, it worked, so after that day I never played Minecraft again.
This is creepy. I do hope you have recovered from it already since that it really creepy. I can't imagine experiencing that for myself. I just hope someday you can find the will to try the game once more.