Go into control panel>sounds/multimedia(speaker Icon). In the audio pull down, do you find your sound card or onboard sound. You might want to take the time to boot into the CMOS: Hit F2 at initial boot, and see if your on-board sound is enabled, if you are using on-board sound, or if it is diabled if you are using a PCI audio card. Try those things and report what you've found.
Noli Nothis Permittere Te Terere!!
EVGA 680i, Dual EVGA 8800GT'S (650/950), 4 gigs OCZ DDR2 1066, Intel Q9450 at 3.8 Ghz, Koolance Water Cooled, Dual Plextor16x DL DVD+/-RW. Dual WD 250gb 16mb Cache Sata 3.0. 3DMark06 score = 19,168.