im usually pretty good at getting stuff to work on my computer but this takes the cake. my fresh windows 7 install will NOT play sound at all. tried different audio ports, legacy drivers, mobo sound drivers and drivers right off of realteks website. i searched here and tried some things to no avail.
I had the SAME PROBLEM, here is how I solved it! Follow these instruction exactly.
2.Once open you should be under the playback Tab, select the proper playback device, double click on that device and another window will open. Then got to the tab titled "Levels".
There should be a bar which on my installation was set at minium (0) by default. Get the bar to a full 100 and it should work. I had the same problem and just as you it took the cake cause it took me about 2 hours to figure it out. lol