Built a new computer with a ASRock X58 Extreme mobo and Windows XP 32-bit. Downloaded the Realtek HD audio driver from the website. Checked the installation and XP says it's just fine. Opening the main panel of the software has a test function in the left panel. Test sounds work fine on both the mobo output (lime green plug) and the case front panel jack hooked to the audio header.
However, playing a video in windows media player does not give sound. Tried both WMV and AVI. Playing a video on ESPN's web site in the browser also resulted in no sound. No Windows jingle on login and logout. Checked every setting I could find. Cranked up every volume knob I could find.