Let me know in the comments which Realtek version finally worked for you. Disclaimer: Always scan downloaded driver files with Windows Defender (or a modern antivirus) before running them.
Open the Realtek manager > Default Format > change from "24-bit 192kHz" down to "24-bit 48kHz" (Studio Quality). Older Windows 7 chips struggle with high sample rates. A Word of Caution Windows 7 is no longer secure for everyday internet browsing. If this is your main PC, consider using this audio fix to transfer your files to an external drive before upgrading to Windows 10 or Linux. However, for offline music production, legacy gaming, or running old hardware—enjoy your resurrected sound. install audio driver windows 7
Your driver is missing. Go back to Step 2. If you have an AMD or Nvidia graphics card, the HDMI audio driver is separate from your motherboard audio driver. Let me know in the comments which Realtek