I can guarantee that your video card has nothing to do with this.
It's either your motherboard or sound card! Check up on those and make sure
they aren't friend or accidently got loose.
Good thing that you didn't stake anything on that 'guarantee'. You are absolutely wrong. HDMI video cards usually have the capacity to route audio through the HDMI connection (GT 220 does) and thus have audio drivers and are a likely culprit if you have lost your audio.