You can get
Silent Hill 2, 3 and 4 on PC, you won't need a PS2 for them. And as for the first game (which is the best IMO, as well as the scariest, despite everything everyone says about SH2), I bet your PC can emulate a PS1 well enough for you to play it.
Blair Witch 1 is somewhat scary, too.
The two
Penumbra games are very good, and they get VERY scary sometimes.
And for a bit of a different experience (as well as for a different and betterdefinition for the term Survival Horror), try the
Clock Tower series. You can even find a translated ROM for the first game, which could be considered piracy, but, well, it's an SNES game, I doubt they still sell it...
Oh, I almost forgot. The
Gabriel Knight games are very good too, if you are into point'n'click adventures. Speaking of which, you can play Yahtzee's
Chzo Quadrilogy, they are very good too.
Finally, if you want to play an
Alone in the Dark game, go back and play the very first one. The Lovecraftian story is the best in the entire series. And while you're at it, you could play the
Evil Dead games too, for a laugh.
That's all I can think of for now.