the only game i ever remember getting freaked out by was Seven Days a Stranger (by Yahtzee) but that may be because i was like 7 when i played it, and i only played late at night by myself. xP
hmm i'm trying to remember if it was one of the resident evil games but... well i just remember this scary game that my brothers used to play where you chose one of 3 crystals at the beginning of the game and it affected everything later. it had some crazy stuff in it, like the walls would bleed when you were freaked out and i remember there being magic spells of some sort...
Thats so weird, I was gonna post this too. I actually found the sequel more scary though. The one in space. Even though its like 8 bit graphics,