My fix to "No sound from laptop to TV with HDMI"
I know this thread was started a few years ago, but I'm currently experiencing the same thing and have found a solution. I'm having this problem with the following equipment...
Laptop - Sony VGN-FW170J (Windows Vista Home Premium)
Television - Sony KDL-40Z4100
AV Receiver - Denon AVR790
My laptop is connected to my AV Receiver via HDMI. My AV Receiver is connected to my TV via HDMI. When I first hooked it up as described, it immediately worked perfectly. The sound stopped working when I changed the receiver input to DVD and then back to my laptop. I was extra frustrated knowing that the sound was working moments ago. I tried everything I could think of to get the sound back. I rebooted the laptop. I shutdown and restarted the laptop. I powered off and back on the receiver. I disabled HDMI in device manager, removed the HDMI cable, restarted the laptop and plugged the HDMI cable directly into the TV (bypassing the receiver). Nothing worked. At all points along the way, "HDMI" appeared under "playback devices" on my laptop, it was selected as the "default device", the volume was cranked up, and the sound bar next to it showed that sound was being played, but nothing could be heard.
I finally figured out a way to get it to work. This solution is with the laptop plugged in to the receiver via HDMI. I go to the receiver menu - "Input Setup" - "Assign" - "Input Assign". From there, I can assign any of the 4 HDMI ports to any of the receiver inputs (DVD, HDP , TV, SAT/CBL, VCR/iPod, DVR, V. Aux, CD, SIRIUS). I use the DVR input on the receiver for my laptop and it is assigned to HDMI #4. What I have to do is reassign HDMI #4 to something other than DVR, so I assign HDMI #4 to VCR/iPod and back out of the menu. I then return to the menu and reassign HDMI #4 back to DVR and exit out of the menu. VOILA! - the sound returns!
I'm guessing that if my laptop were plugged directly in to the TV (instead of the receiver), that there is a similar input menu in the TV that would fix the problem the same way.
The sound continues to go away from time to time, but I can easily get it back now by doing what I described. It sounds more involved than it really is. It takes me 10-20 seconds in the receiver on screen menu.
I don't know why this problem occurs or if my solution will fix everyone's problem - but I hope it helps.