Hey just downloaded f.o. new vegas on steam.. it seems to run very smoothly, but the audio is very late if i shoot my gun and reload i don't hear it for 10 seconds or more later.. dont know what to do.. i have windows xp home edition im not sure if i need a new sound driver or what please help so i can play lol

Post a dxdiag: http://www.gamesas.com/topic/1122570-how-to-dxdiag/
Use the spoiler selection from the special bbcode menu. See the 3 buttons on the top left? Click the right most button.
Copy and paste the dxdiag there.

The sound card driver is where I would start.

Also FFDShow is known to cause sound issues.