No sound through HDMI, already set to default

Hi,

I have a GTX570 which I use to connect my PC to my TV via HDMI. For two years or so everything has been fine until I recently returned from holiday and the picture still works but there is no sound. I have googled the problem and the usual answer is to set the TV as default in audio properties. I had already done this and it is set as default (shows full name of TV).

When I click test the green bar goes up and down to show sound is being played but it just doesn't come through the TV. Another solution I have found is putting a cable between the sound card and the graphics card through SPDIF but this doesn't seem to be required as it has always worked without this.

Please can you help I am pulling my hair out.

Thanks for the welcome and response. I should have added I have already tried that, with two other cables. I should also add that this is run through a wireless HDMI send from upstairs to downstairs. This has always worked in the past with no issues. I have tried different cables both going into and out of the sender and receiver respectively. I did plug in a different TV (same make, LG) directly to the PC and it worked but it did not work when plugged into the wireless sender. I know it sounds like an issue with the sender but it is still transmitting the picture with no issues and as I said it has always worked in the past.

This is the transmitter/receiver kit, I got it ages ago. Xenta Wireless HDMI Kit - WHDI HDMI Transmitter and.. | Ebuyer.com has been fine until now.