Main speakers A and B not working...

Adjust the input control on the receiver to 2nd zone.

go to audio set up and configure the system for 5.1 or higher sound output.then only all the speakers ll work

champ natwork problem

You need to install a updated Sound Driver or you will need a new sound card

When watching TV or VHS the sound should be stereo and therefor come out of the the 2 front speakers. I suspect you now have sound out of the left front and the center speaker which indicates you connected the center speaker to the right front speakerterminal and the right front to the center terminal.

Just check if all speakers are connected to the correspondent speakerterminal.

If this is correct and the problem persists, try to connect another speaker to the right front terminal to see of the terminal or speaker is not working properly. If another speaker does work on the same connection, your right speaker might be damaged which might not be heard when listening to 5.1 because of the surround sound.

Your speaker system is designed for the 5.1 surround. *********** board manual shows you which wire goes to where. 

when the stereo or mono listening mode is selected only front speaker and subwoofer produce sound--------make sure that speakers are configured correctly.
and you select surround sound in listening mode.

More than likely the protector circuit is getting activated... You can't go below 6 ohms on the surround back which means you need 12 ohm or higher speakers for outside (since the two outputs for surround back/zone2 are in parallel). As a simple diagnostic test, disconnect one speaker and see if the sound survives longer than 2 seconds.

this isnt a solution to your problem but i have a suggestion. I see this problem has been posted a couple days now and i think that because your problem looks like it involves more stereo equipment rather than the xbox 360 console. i think you would get a better answer actually a soltuion if you posted this in the stereo section.

Two possibilities for the no sound on the main speakers:
1) May be caused by the lack of the pre out main in jumper on the back of you reciever.
2) Check to make sure the -10db selector is not stuck between positions.