Vista/No Sound/Failed to play test tone

i have recently upgraded to vista and found out that i have no sound. the driver (vista version) for my on board sound card seems fine but when i try to play a song on windows Media Player, i get a msg of  "Windows Media Player encountered a problem while playing the file. For additional assistance, click Web Help."  and i also get a "Failed to play test tone" msg when i try to test my speakers. i thought it was because of vista dosent support my crappy on board sound card so i got a new one.

i have just installed a Creative Audigy SE and have downloaded the driver for windows vista. again, in device manager, everything seems fine, the driver is fine, the device is working. but i still get the "Windows Media Player encountered a problem while playing the file. For additional assistance, click Web Help." when i try to play a song, as well as the "failed to play test tone" msg when i click on the Test button. please help me, i am tired of using a computer with no sound.