I have not heard of anyone else with this problem so I'm turning to here. I am running Win 7 Ultimate RC1 on my Dell Inspiron 6400 Core Duo 1600mhz. 1 gig ram ati x1300 descretegraphics and sigmatel onboard audio. After I installed win 7 I installed the drivers for the sigmatel sound and the sound worked but all of a sudden I couldn't open the "sound" option in the control panel! So I uninstalled the sigmatel drivers and now I have no sound at all after reverting back to the windows driver. What the !!!??? Why wouldn't/won'tthe "sound" option open and how did reverting back to the windows driver kill my sound completely?-B