Now I haven't been able to find this answer anywhere before so I thought that I would share this with the world.
After installing a video card into the HP dc7700 SFF (I used a GeForce G210 Low Profile), I've noticed that a lot of people were having an issue with no sound from the onboard media card. The solution is actually quite simple and a lot of people said that what I am about to say is not possible...
So to get your audio working again all you have to do is follow these 6 simple steps;
1. Enter the BIOS Menu
2. Go to the Advanced tab
3. Open Device Options
4. Enable Integrated Audio
5. Apply changes and exit
6. Log on and test your sound and enjoy!!
Pretty simple, and to think....I searched for several hours and couldn't find a single answer on how to get the audio working again.....
I do work for HP, have 15yrs technical exp, and love tinkering and exploring my systems so finding this was more fun then the games I'm now playing!!