ATI 3870 and Lost Sound

I've already posted this issue on a game forum I play, so I will simply copy my posts here:

"Alright, I JUST installed a brand new OCZ 600W PSU, 2 more gigs of ram, and a SAPHIRE 3870 card about 20 minutes ago. I turn on the computer, and my sound is gone! I go to the control panel, (I have vista) and under the sound menu, it detects no devices. i go to my device manager and under the Sound Video and Game Controllers list, there is a "High Definition Audio Device" installed, up to date, and enabled. Under System Devices, there is a High Definition Audio Controller" installed, up to date, and enabled. Still nothing on the sound menu though, and any time I try to play a file (.mp3) with windows media player to test the sound, I get a pop up saying there is no sound device. Any ideas?"

"Well, I removed the graphics card, and sound worked fine. The sound applet detected my speakers, and everything played fine. I put the graphics card back in, and wound up right where I started. No sound, no sound device detected. Any ideas?

Some possibly pertinent info: The monitor must be plugged directly into the graphics card, into what I believe is an HDMI port. I don't have an HDMI cable, so I am using an adapter that came with the card. I do not have speakers on my monitor but rather plug-in speakers."

Computer type: HP Pavilion a1710n
Sound card: Whatever this thing came with

The issue is, I'm not seeing ANYTHING in the sound settings on the control panel. No devices at all, not even the HDMI sound. Under my device manager, I have tried to update the drivers on everything with the word sound, and it says they're all up-to-date.