New graphics card, no sound except static, Windows thinks all is well

[requinix]

(second attempt at posting this, sorry if both worked)

Short version:
- Video card died, tried two others and video is fine
- ...but there's no sound at all except for EMI static
- ...but audio works again with the dead card back in
- Windows shows everything working: speakers enabled, meter shows activity during playback

Long version:

My MSI 660 Ti finally died after many months of death throes*. Audio worked fine.
I had an old 9600 laying around so I put that in. Video worked fine but there was no sound - repeat, NO sound - except for what I think is EMI static: mostly white noise, some "popping" and "scratching", and it varies according to computer activity (what windows were open, CPU activity, etc). Put the bad card back in and was able to boot Windows without any video: sound worked fine. Put the old card back in, no sound.
The 660 was still under warranty so I RMAed it; they couldn't fix or replace it so they upgraded me to a 770, which has slightly improved but otherwise similar stats. No audio with that either. Note that I can't try the 660 anymore because MSI has it.

Now I've been looking around for explanations and none of them fit/none of the solutions work:
- Microphone? Disabled
- Bad speaker configuration? Windows shows the right configuration of speakers, the speaker playback device is enabled, and the meter shows activity when playing audio
- HDMI conflict? Disabled those devices, even all playback/recording devices but the speakers, in the sound configuration and the device manager, no difference
- Driver problem? Uninstalled and reinstalled, no difference. An NVIDIA driver update just happened recently so I did a clean install as always, including its HD Audio driver, but no difference
- Physical problem with the jack? One on the front has the same problem
- EMI? Moving cables, outside and inside the case, does not seem to affect sound
- Speaker problem? Tried headphones, no difference
- BIOS configuration that changed when replacing the video card**? Only has options to (a) enable/disable, (b) change HD/AC97, (c) something else I forget. Tried the four possible configurations of B+C, no difference

Disabling the audio device itself cuts out the sound entirely (including static). There's no static during boot until Windows begins loading. No alternative OS available.

The only cause I can think of is that the 770 isn't latched into place in the PCI-E slot. The problem is that the plastic "case" on the card is literally a few millimeters too large and depending which slot I try to put the card in it hits: some SATA ports on the motherboard, and/or a PCI slot which is a tiny bit taller than the PCI-E slots, and/or the latch on a PCI-E slot. I may or may not file down or cut out the areas on the case causing problems. I can't remove the case entirely as the two cooling fans are mounted on it.

So. Any ideas?


* Cold boots would often not show video until after a few resets/power cycles. Would POST fine and Windows would load, as I'd hear the login chime, then I'd use the keyboard to power off/restart (which I can do from memory). This wasn't really a problem as I rarely turned off the computer. However I just moved and had the computer off for a couple days; I spent an hour resetting/cycling to no avail. Then the POST check started failing *occasionally* on the video card, as indicated by lights on the motherboard.
** Unless the BIOS could remember past video cards, this wouldn't explain why I could put the bad card back in and get audio again.

 

[requinix]

After some more searching I've found other people with the same motherboard who had the same problem: eventually the audio just stopped working. I did the same thing they did and bought a (relatively) cheap sound card. Works fine. Computer is getting a bit old so I'll probably end up building a new one sometime this year anyways.