Penumbra series: The game crashes - Have recently changed sound settings and/or using SoundBlaster X-Fi.

If the game has previously worked but is crashing after having changed the sound settings, see below on how to reset the settings.

Depending on game: Open "My Documents/Penumbra Overture/", "My Documents/Penumbra/Black Plague/" or "My Documents/Penumbra/Requiem/" and delete the settings.cfg file. This will make the game use the default settings next time it launches.

If that does not help, check to see if there are any new drivers available and install them.

If that does not help user Lars sent the tip to:
If using a X-Fi changing the sound card to "Game Mode" from "Entertainment Mode" helped resolving issues with crashes related to using hardware and EFX options in the game.