For those having sound problems, this seems to be a problem with your computer rather than the game and the reasons could be many (drivers, version of windows (or whatever you use), another program messing your configuration, etc.) so I'll list a bunch of things that helped other people. In my case I started not being able to open the game, then was able to open it but with no sound (that also proves the crack works), and at the end I gave up.
- Update DirectX (didn't work for me).
- Install the DirectX that comes with the game and appears during the installation. (this should be all you need since the game chooses the files required to run it. But didn't work for me).
- Update your videocard drivers (also didn't work for me, using NVidia GTX series).
- Install DirectX Software Development Kit and DirectX End-User Runtime (I managed to launch the game with this, but with no audio and can't select something from the options).
- Update sound drivers. (Didn't work for me, using realtek HD drivers for MSI).
- People using ASUS reported deleting Sonic Studio 3 and Sonic Radar 3 worked (the programs were messing with the configuration). With MSI deleting Nahimic 2 worked, with alienware removing Alienware Sound Center worked. (I don't have any of those programs, so this didn't apply to me, also consider deleting programs could be harmful to your computer, so be careful).
- Make sure this isn't a problem caused by a windows update, specially on w10. (not my case, using w7).
- Disable audio drivers and reinstall them from scratch using the latest version from the official page. (didn't work for me, but at this point I found a problem with realtek and MSI sometimes the very useful sound manager disappears after reinstalling the realtek drivers, and the best solution at the official forum was to reinstall windows).
- I used restore windows to a previous point, I'm back to not being able to open the game, but sound manager and all else is back how it was before. Screw this.