Hi, I own 3 of Bethesda's games. Oblivion, Fallout 3: GOTY, and Fallout: New Vegas. All of these are legit copies of the game bought through Steam (With the exception of Oblivion, I got a disc version of that). But lately, the sound has been kinda screwy. See what happens is, that at random times during the game, ALL sounds will stop, except for the background music. I can't hear me walk, shoot, attack, talk, etc. The radio also starts to loop a segment of whatever is playing. This happens in ALL of these games and the only way to fix it is to completely exit out of the game and restart, and that doesn't keep it from happening again. I'm pretty sure I updated my sound card and it does not happen in any other games. (It BRIEFLY happened in Team Fortress 2, a game by Valve, but it stopped doing that a long time ago)

Bump

The sound card could be overheating. If you haven't done so recently, open up your computer case and carefully blow out any dust and debris with a can of compressed air. Do not use your own air because you'll just wind up blowing it into your face and you'll add moisture to your components that doesn't need to be there. If you don't have a can of compressed air, a small vacuum cleaner or a low power air compressor will work as well.

I clean it out weekly. It's not the sound card. And if it was, wouldn't it be for other games, not just for Bethesda's games?

It depends on how taxing those games are on your hardware. If you've already cleaned it out and updated the drivers, have you updated DirectX 9.0c? Also, I think I read something about codecs either missing or assigned wrong can cause the radio to not play properly. A search for codecs should turn something up, but I may be thinking about the radio "popping" and not the sound going away. Still, if you can fix the radio, that might fix the other sound issues. By the way, you didn't mention what OS you're using. If it's Windows Vista or 7, you may have to either turn off the User Account Control (UAC) or move your games out of the Program Files (x86) folder if they're installed in there. For some reason, Vista and 7 automatically install 32-bit programs in there and refuse to give them the proper system access they need. I usually put my games into a subfolder of my Games folder off of the root.

UAC is off. It's windows 7 64 bit. Games are not in x86. Still have issues. I'm also having it in a few other non-bethesda games too though :\

Found a few games in the x86. Moved 'em. Didn't fix it. Moved 'em back.

What sound card do you have? It may be something to do with the card itself. I hate grasping at straws, but I don't know what else to tell you. My method is usually:

Make sure my system is clean (chkdsk and dust blowout)
Update drivers
Update DirectX
Check for patches
Do an Internet search for my hardware and software combination (e.g. using a Realtek board with Fallout3).

I've done all of that. And for the last part, there's nothing. Random things that don't relate to each other and none of them are MY problems. I have the Realtek ALC892 for my on-board soundcard. I don't have a dedicated one.

Find your fallout.ini and change the line: iMaxImpactSoundCount=32 to iMaxImpactSoundCount=64. Hope this helps.