Have no audio playback..

I seem to not have any audio playback..I have a Lenovo IdeaCenter K Series K2.3 Pentium dual-core E2180(2.00GHz) 3GB DDR2 500GB Intel GMA 3100 Desktop with Vista Home Premium and for some reason when I plug in my headphones into the jack, I hear no sound (and its not muted)..Any ideas? Matt

try changing the default audio playback device.

I actually fixed it by reinstalling the drivers..Thanks for the suggestion though and sorry to jump the gun