Okay, this is driving me nuts.
I wanted to play NOLF2. Again. For the xxx time. Can't help it, just love the game.
So I grab my copy (legally bought one, the one I've always used) and install it. I'm on Win XP Pro SP3. No problem. The install ends, I configure the game and launch it. Still no problem. I see the opening cinematic, I start to play (the ninja village) everything runs smoothly, with all the due sound effects, dialogues and music.
Then I save and close the game. Turn off the computer.
Later that day, I want to play again. Launch the game... and there's no sound anymore! there's the music in the menus but as soon as I'm in game, no sound anymore...
So, I uninstall the game, reinstall it. NO SOUND!! even in the opening cinematic, which was working perfectly before.
I have to say that I didn't touch or change anything between the moment I played it with sound and tried it again without sound... My drivers are up-to-date and haven't been updated between the first time and the second time I played NOLF2....
I also tried to install it on my other computer (Win7 Integral 64bits): the game runs well.... but with no sound!!!!!
If somebody can help me fix it, I will be eternally grateful...

From this post a quote :
"In my experience, codec packs are often the cause of game sound problems. Some games install their own version of specific codecs and if another similar one exists it can cause conflict.
I remember No One Lives For Ever 2 didnt like a certain codec pack being installed as it conflicted with its own version of an mp3 codec.
All i can suggest is that you uninstall any codec packs you have then just get the individual codec installers for the video types you use. There will no doubt be a lot of codecs in those packs that you never use anyway."

Wait for it to come to GOG. ;)

Hmm, it's true that during the NOLF 2 install, there's the installation of a sound codec... And it's true that I have a codec pack (video + audio) installed. But then, why it doesn't work on Win7, where I don't have any codec pack installed?
Nevertheless, your remark is interesting and I might give it a try.

If you installed on Win 7 with autorun, you may need to uninstall, delete all the NOLF directories and install by right clicking the setup.exe in Windows Explorer and clicking "Run as an administrator" I would turn UAC off as well.
After installing, right click the game shortcut, click Properties, click Compatibility tab and check "Run this program as an administrator" On Win 7 I uncheck "Run this program in compatibility mode for" to start with and only use it if necessary starting with the latest compatibility and working backwards.
In some cases you may need to install the game in a directory outside of Program Files as UAC can interfere with some read / writes. Create a directory, I use C:\Games, right click the setup.exe in Windows Explorer and click "Run as an administrator" in the resulting dialog. On the installer, point the install to the new directory. Also set the shortcut to "Run this program as an administrator" as mentioned above . . . =)
Edit: Sorry, forgot it wasn't a GOG game . . . =)

No problem ;)

For others that may have sound problems, codec packs can blow the sound on this game. I remember this from when it came out - actually had to do an OS reinstall to get sound back. If I'm not mistaken - the game installs some windows media based codecs (sound and video). I recall the game could have similar behavior - working on initial game start but sound issues after a reboot or relaunch, etc. Even if you haven't had any codec packs installled it could be related to those older windows media files being installed and not behaving with your current windows media config.
Ever since self-contained codec players like VLC or GOM I haven't had to deal with "codec hell" in years.