Troubleshooting a Denon AVR 888

For some odd reason, all the sound wants to come through just the center channel and the subwoofer. Nothing at is coming from the other four speakers. I'm not much of a techie so reading the pdf of the manual is like cracking the rosetta stone for me. Just wondering if anyone knew of an easy "reset" for this model. Thanks in advance and I apologize if this seems like a moronic question to ask of a bunch of audiophiles.

 

AVR888 reset?

• turn OFF using POWER;
• press and hold POWER;
• while still pressing on POWER, simultaneously press on SPEAKER A and SPEAKER B;
• release buttons when the display flashes.