Please Help!

[JNolan92]

A few months ago, I ordered Amnesia: The Dark Descent from GameFly and everything was running perfectly fine. The other day, I had to do a reinstall on my computer and when I reinstalled Amnesia and entered in the correct serial number and everything, the graphics were very dark, even the menu. I could not see the stone walls in game and only shadows and I could barely see the wooden doors. I did a system restore to early on in the day and when I went to start the game, the executable was missing. I re-pasted the Amnesia folder from my USB flash drive onto my PC and when I went to start up the game, I did not have to re-enter the serial number and the game was still dark and everything.
Is there some way to fix this? Please help!

EDIT: By the way, I'm running Windows XP

[plutomaniac]

Reinstall the game from the official installer, not via copying files from USB sticks. Then make sure your graphics card drivers are fully updated and reinstalled cleanly to repair any corrupted files causing problems. For the latter, check Questions 2 & 3.