Users of ATI X-series! Look here for DEMO fix

[mansarde]

Okay, so I downloaded and unzipped the folder, but I don't know what you mean by "Unzip this into the demo install directory so it replaces Amensia.exe" That is my lone problem. Anyone have any ideas / help?

If you bought the game from Steam, then the "amnesia.exe" to replace should be in this directory:
"Steam\steamapps\common\amnesia the dark descent"

If you bought it from Frictional Games directly via the Amnesia website, then it should be in
"Amnesia - The Dark Descent\redist"

And both of these folders should of course be in your "program files" directory.
If you're using a 64bit Operating System, then the folders should be in "program files (x86)".

This is all assuming you didn't change the default directories during installation!
I hope this cuold help, good luck and have fun with the game! You certainly will

Edit: Ninja'd by Kuni. But since you can also have the steam version I guess it's ok to have two answers.^^