I like everyone else waiting to play started a new game on release. Upon the first second of realtime game play I was suddenly staring at a fan. I realized after a minute of nothing happening something was not right. I heard no voices and suddenly my character jumps up and starts staring at a wall. After hitting (Escape) and the (~) Keys a few times. It seemed to help things like voices and events move on. Hitting escape over and over after every spoken sentence of text and the ~ key is not the proper way to play the game obviously.

Things I tried to fix the problem

• Uninstalling all drivers audio and video then updating to the most current version.
  
• Doing a couple of clean installs
  
• Tried using the K-lite codec pack and then tried the cccp codec pack. The K-lite codec pack fixed any issues I had in fallout 3. No success for me in New Vegas though.

I am currently running Windows XP.

I'm having this same problem, as are many others. There are a few threads about it on the second page, but it seems no one has found a solution yet.

Edit Notes: I noticed When I uninstalled the codec packs that New Vegas would crash after the first splash screen. Only when I had a codec pack installed would the game let me in the main menu. It also appears that the in game radio and attack AI seems to be affected. When someone is aggressed they just turn red and stand still.