Onkyo - dvd player connection problem

Hi, just bought an Onkyo home cinema system (TX-SR674E) but i'm having problems connecting my Philips DVD player to it. Currrently there is no sound or picture. I am using an S-video cable to connect the DVD player to the Amp (an an optical cable for sound) but am unsure whether I should be using another cable to connect the Amp to my television. I currently have an HDMI cable connecting my PS3 to my TV (via the Amp) and thought this cable would suffice as the connection for the DVD player to the TV. This particular AMP has HDMI upconversion so presumably the connection to the TV would have to be in the form of either an HDMI or Component cable? I've tried changing some of the video input settings but this hasn't worked. Thanks for any help you can provide.