I can't really help you out, I don't know what type of hardware you had, you'll have to find the correct sound drivers on the web.
You can also try:
- Verifying game cache
- Uninstalling useless addons and only keeping the ones you use,
- Uninstalling the game and have a fresh install, only with TTT and CSS content or whatever you play.

I can't really help you out, I don't know what type of hardware you had, you'll have to find the correct sound drivers on the web. You can also try: - Verifying game cache - Uninstalling useless addons and only keeping the ones you use, - Uninstalling the game and have a fresh install, only with TTT and CSS content or whatever you play.