I have finally bought my very first Home Theater (5.1 dolby). However upon connecting the speakers and playing the VCD, only the 2 front speakers and the sub-woofer are working. The center and 2 rear surround just Hum with no sound. I have double checked the connection and all seem Ok as per the manual. Where could I be going wrong. I also noticed that the sound from the movie appears to be slightly delayed. Any solutions. The Brand is PERFECT IMAGE model DHT-100S