One way to help with sound problems worked in fo3 and oblivion and and.. turn off music as in turn the slider all the way down.

I had horrible sound issues with this game yesterday.

I fixed them all by uninstalling my codec pack (vista codecs). My install was over a year old. Once I confirmed this fixed things, I downloaded the latest release of the codec pack and everything is still working well.

Hope this helps.

If anyone is using a Creative Labs sound card on a Vista or Windows 7 system, first try installing Alchemy from Creative Labs' website and add Fallout Vegas to its games list. This fixed a few audio issues for me without having to apply all these odd process priority and codec adjustments.

Uninstalling my audio codec pack fixed the missing sound issue, however now whenever a NPC or other sound effects audio track is playing the game goes into super-slow-mo mode but no drop of framerate, makes the game completely unplayable.

I had a problem with no footsteps an gunshots sounds after few minutes of playing. I've tried to reinstall drivers, unistalling codecs, setting priority for process and other. But this doesn't works in my case.

Yesterday I've found solution that works for me in WinXP: click at FalloutNV.exe file and set "run file with win 98 compatibility" (I don't know how it exactly named in original windows version, cause I'm using russian windows copy). I hopes it'll help you.

putting a copy of d3d9.dll in the new vegas folder solved all my slow-down and missing sound issues. Game is still bugged to high hell but at least it's playable now.