Hi,
Please do try these troubleshooting steps that may help.
- First is to check if the default Playback Device is set properly.
- Right click on the speaker icon and select Playback Devices.
- Once open, right click on your TV that is listed and select Set Defaults.
- Click Apply and OK then test it again.
- If it will still not work, do uninstall/reinstall the sound card driver.
- Open Device Manager and uninstall the Sound driver.
- Once uninstalled, reboot the laptop and it should reinstall the driver automatically after the reboot.
- After the reboot do check if the TV is set as the default Playback Device again.
- If it will still not work run System Restore and restore it back to an earlier date when it was working properly.
- Here's how to run System Restore:
http/windows.microsoft.com/en-PH/windows-8/restore-refresh-reset-pc