Please perform the below mentioned steps and check if this fixes the issue:
1. Right click the Volume icon in the bottom right side of the screen.
2. Select "Playback devices".
3. Check if you can see "HD audio" or similar options listed here.
4. If it is listed please make "HD audio" as the default audio device.
5. If it is not listed here, right click any empty space and check the option "Show disabled devices".
6. If the "HD Audio" is still not listed try updating the Video Card Drivers and then check again.
by going in to the sound options on my computer (which you can access in your control panel) then set your sound default as HDMI. This should solve the problem, just remember to set the default back to the laptops speakers when you are finished using it on your TV.
I hope that helps.