Sound not working on L4D (PC)

[CalipatFootball]

For a while, my No Mercy- Apartments file for Co-op hasn't been working, so today, I decided to reinstall my game. After it finished installing, I started up the game, and I noticed that the sound wasn't working. The sound works on the "Valve" screen, the opening cinematic, and I can also hear fellow players talk through their microphones. However, I can't hear ANYTHING on the menus, or in-game. Can someone please help me with this problem?

[FizixMan]

Try reinstalling again?

[kidkiller745]

check options and adjust the volume?

[DethPenguin]

Did you turn on your speakers?

[FizixMan]

Did you turn on your speakers?
He said he can hear the opening logos and people speaking...

[zombicidalmaniac]

For a while, my No Mercy- Apartments file for Co-op hasn't been working, so today, I decided to reinstall my game. After it finished installing, I started up the game, and I noticed that the sound wasn't working. The sound works on the "Valve" screen, the opening cinematic, and I can also hear fellow players talk through their microphones. However, I can't hear ANYTHING on the menus, or in-game. Can someone please help me with this problem?
exact oppist of me i can hear everything but no video for the game.OT did u plub ur speakers in the right slot thats wut wwas wrong with mine

[Keptron]

You tried to get new drivers? I only loose sound when my speakers turn off by it self ( yeah, it looks like to be alive o.o )

[CalipatFootball]

I'm gonna try to reinstall it next chance I get. But I know it's not the driver. I tried verifying the files, and after it finished, it went straight to reinstalling it, so we'll see how it goes