Surround Sound from PC to TV

[kostakis]

Hello there,
I am trying to set up this. From the VGA card ( PCI-X MSI Nvidia GT 640 2Gb) i have a HDMI cable connected to my TV ( LG 42LE5300 ). Then there is a Optic cable from TV to the receiver ( LG HT805TH 5.1 ). Sadly only the 2 front speakers are working. The rest is off. Any ideas if it's possible to set up Surround System and if so , how ?

Thank you in advance,
Kostas

 

[shadowed]

Have you changed computer sound software to surround ?
Are you plugging a HDMI cable to an VGA adapter on the video card ??? There should not be any VGA on that card ?