I have a sony sound ambience system.I turnedoff Goto turn it on again . It works but no sound .Afriend look at it and they saidholding another? button down while turning it off/on? not sure which is w

SOURCE: TV will not turn off and TV buttons preform the wrong functions

check D1004 5v zener diode, if defective it can cause you this type of problem, also check D1003 and D1005.
part # 8-719-929-15 from sony.
these diodes are located in HS board, the one where all your front button are located in. by the way the HS board is no longer availableffrom sony

SOURCE: No main menu, just wavy lines with sony entertainment

This is a hard reset of the system, used when there is a catastrophic error etc. I have trawled these kind of sights and the main concensus is to ensure you have a back up of all important data. I experienced the same issue but the method above was advised by my games shop.

SOURCE: have sony home theater system Sony Compact av system dav-fc8

CHECK YOUR SPEAKER CONNECTION THESE UNITS HAVE A SAFETY RELAY IF YOU HAVE A PARTIAL SHOT EVEN A SMALL PIECE OF WIRE TOUCHING THE OTHER TERMINAL IT WILL NOT ALLOW THE UNIT TO OPERATE THE FAULT MAY BE INTERMITTENT

SOURCE: i dont have a manual, somehow ive turnedoff wireless. how do i turn back on

There is a wireless ON/OFF switch on the front edge of the notebook, left most button group. Here's the manual

http://support.acer.com/acerpanam/manuals/acer/0000/userguides/AS9500-ENG-OLM.pdf