sony bravia dav dz170 home theater system

Hey guys, I am new here and this is the first time I have posted. I am a bit of a beginner with this. I have currently got a Sony Dav-DZ361W. Which is a home theatre system. (this is 850w rms) I have being offered a Sony STR-DE400 which is a 5.1 AV Receiver. (I believe this is 450w rms) I have...

Last night I purchased a Sony Bravia DAV-DZ170 all-in-one home theater system. It came with speakers, a woofer, and a DVD-player/receiver. I'm having a problem getting blu-rays and video games to play in surround sound. I have the receiver hooked up to the tv via an optical line. My ps3 is...