Sound says it works, but no sound comes from speakers

[aflock]

Ok well I recently upgraded my PC to Vista Ultimate, but have encountered a problem with my speakers. My USB headset's sound works fine, but when I switch to my speakers via "Playback Devices" no sound comes out. When I play a video, I can see the sound moving in real time, but still no sound comes out. How can I fix this?

-Thanks in advance.

[Robel11]

If there is no sound and there is no light, then it is an electrical power
problem. ... If none of that works, then something died and cannot provide you
with power any longer ... (Where do these come from ). If any of these are not a
genuine ... Your speakers arnt working they were working but you went to the
bath ...