Hi Korvan, welcome to Sysnative!
Now I have not since this problem started tried playing another full screen game, but prior to this like a few hours mass affect 3 had no problems playing sounds in game.
Do you mean to say that this problem has been happening in other games as well? Are you only experiencing this problem in Delta Force Black Hawk Down, or is it a general problem affecting several games? If it's affecting more than one game, please list all the games you can remember that are affected.
Delta Force Black Hawk Down is quite an old game (released 2003), designed for Windows XP 32 bit. I've had similar problems with games before, where the hardware I'm using is not supported by much older games. I'm currently looking into the problem to see if this is a common issue with this game on Windows 7, however I can suggest you try running the game in Compatibility Mode.
Locate the Program Files for the game, and locate the main executable for the game (I believe this is C:\Program Files\Novalogic\Delta Force Black Hawk Down\DFBHD.exe - I may be wrong). Right click on DFBHD.exe and select the
Compatibility tab. Check the option "Run this program in compatibility mode for:" and select Windows XP Service Pack 3. Click Apply > OK, and then try running the game.
Has this made any difference?