When I first run a game, it runs okay, sound and music is fine. If I exit the game however and want to play it again or other GOG game, It doesn't plays sound or music, any game. That is confusing, I have to retry many times, reboot Win 7 or unplug the HDMI connected to my TV (I play games using my VGA monitor and audio jack external speakers, not HDMI.

So, why does it happen? It's annoying.

Have you ever tried running the game in compatibility mode.. or reinstalling the game..

The games are running fine on mine I'm also using win 7.. if that's the case maybe check your computer for technical problems maybe it's your pc and not the game...It really depends..

I had a similar problem recently, and as cliché as it sounds, uninstalling and reinstalling the sound driver fixed it for me. Have you tried that? Can you play music files in Windows? In my case, Windows kept complaining that the audio device is already in use by some other application.

Had this too a few years ago. A game changed my sound driver without asking for permission nor giving notification about it.

The problem is in drivers, I have the same problem but only in skype. It appeared, when I was talking with friends - suddenly the sound was gone. Reinstall or install new drivers.

You need to disable any HDMI sound devices in your audio manager. You may not have HDMI sound, but the computer is capable of sending sound through HDMI and is selecting that as a preferred device

You need to configure Windows to set the default audio device to be the primary speakers that you want everything to go through normally. Any additional outputs to TVs or other devices should not be the default. All software by default will output to the default audio device unless you configure it to use an alternate audio device instead. If your output is configured to HDMI TV and the TV isn't on, most programs will be sending the audio to the TV which is not on so you wont hear it. Additionally, not all games or other programs have a way to let you configure another audio device, which is why it is important to make Windows default to your normal computer speakers that are always on and available.

If you like to play games on your TV sometimes also, then you'll either have the game on the TV and audio coming from your computer speakers, or you'll need to go in the game's settings and configure the game to use the HDMI audio if it has the ability to do that, then switch it back to the computer manually when you want it to work on the computer speakers again. If a game does not have the option in the configuration screens, then you might need to search the web to see if there is a way to override it via a config file or something. Otherwise the only way to switch audio between multiple outputs for programs that only support using the Default device, is to constantly reconfigure the Default device in WIndows every time you use those games/programs, and change it back when you're done.

Hope this helps.

It's been a while since I last posted this. Thanks for all your replies. This is what whas going on:

I do play on the TV using HDMI.
After a few plays, no GOG game emmits sound, though everything else works fine.
If I change to regular speakers (not the HDMI sound), the problem keeps the same.
I tried running a Steam game and sounds good. Then chage back to a GOG game and the problem is solved.

I have an NVIDIA sound driver, I am trying to update the driver.