You have realtek ALC 650 like me
, did you run direct sound test completely ?(at sound tab). because you got failure and I think you pressed no buttun during direct sound test . your result shoud be like this,
http://balder.prohosting.com/khafan/Soundtab.jpg
I think there is a error in direct X files, try reinstalling direct X and you can also go to direct X files tab and check for files problem. this a pic. of my direct X files tab,
http://balder.prohosting.com/khafan/DXFilestab.jpg
Your realtek dirver is very old. you can get new driver from realtek.com.tw unfortunately their server currently is down, here is a mirror link that you can get new driver,
ftp://152.104.125.40/pc/ac97/alc650/wdm_a345.exe