Disclaimer: I don't actually believe in the supernatural. This is just for fun since it is Halloween time.
The earliest gaming computer my family had (that I remember) was a Commodore Amiga 1000. The games on this computer terrified me, even non-horror ones like Roger Rabbit and The Three Stooges. To this day, there is something about old computer games that gives me the creeps; it's something about the sound design and the graphics. In particular, a game called IT Came From The Desert has haunted my dreams. To this day, I still have dreams in which I am forced to play this game or am living the game, and the computer won't turn off or pause or anything. Most of the time, the game is actually different, but it's supposed to be this one. Oddly, I only watched my brother play this game, only attempting to play it myself once some years later. However, my brother has indicated that this game still haunts him as well (I'm not sure if in dreams or just a general terror). This terror extends to the computer as well. The Amiga 1000 itself seems haunted to us. Four years ago, I tried to get the Amiga up and running again (and failed), and just its presence on the kitchen table unpowered was somewhat disconcerting. I tried to face my fears by watching a longplay of the game a little while back, but it did not help.
Similarly, the game Return to Zork scared me to the point that even seeing the CD case in my room freaks me out a bit.
I also regularly have dreams in which I am stuck in an old school 2.5D Doom level fighting hordes of demons. These are not quite scary, more so restless and stressful.
Has anyone else had a "haunted" or "haunting" computer or computer game?