Need to install Directx 10 or 11?

I have a typing program for my computer and a few of the games on it are not working. It says "Unable to initialise Direct sound 8" I was told that in order to fix this problem I need to install BOTH Directx10 and 11.

My computer has Windows Vista and my understanding was that Directx11 runs on Windows 7, so maybe I don't need to install that one after all. I have Directx 9.0 on my computer. Does anyone have a link where I can download one or both of these? When I go to the Microsoft Windows website there are a bunch of Direct x downloads and I am not sure which one I am supposed to be downloading. Any help would be appreciated.

Kendra
 
I already downloaded the full version of Directx 9 and that still has not solved the problem. Most of the game components work, but there are just a few games that say "Unable to initialize Direct sound 8, please check drivers". Is there anything else I might be able to install to fix this problem?

Kendra
 

redk

TS Rookie
Sounds like it may be a sound card/driver issue.
What sound card are you using in your computer, and how old is it?