Computer Problem: Unable to hear Sounds

[cyberSTACK]

Hi,

I am having trouble hearing sounds on my desktop. I can hear music fine via itunes, but I cannot hear the sounds when I receive an IM, or the poker sounds when playing on party. It seems like all software sounds are not working.

Does anyone have any idea what this could be? I recently moved and had to setup my computer at my new apt and now I cannot hear sounds.

Please help, thanks!