If you go to page 1-18 in the manual all will become obvious.....

If you haven't got a manual then you can download one (in PDF format only) from

http://www.asuscom.de/pub/ASUS/mb/so...98_a7v8x-x.pdf

Without the jumpers in place on the front audio block you will have no audio...

Factory default is as illustrated in the manual.

John