Connect computer and TV to AV receiver, but sound only out of 1 speaker?

Finally got my lazy ass in gear, and set up my Kef 5.1 speakers, connected them up to the AV receiver. I also connected my TV to the AV receiver using a HDMI to HDMI cable, and then another HDMI to HDMI cable to connect my computer to the AV receiver.

The visuals are how I want it, with the TV acting as a 2nd monitor (i play all my media from computer and put it up on tv screen), but I am having an issue whereby the sound is only coming out of one speaker. My computer seems to be detecting the Sony TV, but not the AV receiver in between, it's acting as if it's connected direct to the TV (not sure if that is how it is supposed to be).

Does anyone have any ideas why this is happening?

Right this is weird, but i shutdown everything then started up PC, once that was up, then started up AV receiver. Computer then picking it up. Switched on TV, computer now picking up the TV.

On the computer, changed speaker config to 5.1 for the TV, then on AV set mode to 7ch stereo, and sound came out all speakers.

Now need to see if subwoofer is working...during test it was very low bass, i am guessing i need to play stuff at much higher volume for any bass to be noticeable, but as its night I cant exactly do that, so will have to wait until tomorrow.

Check your wires are correct.