Gaming Audio Out Port in back not working

[Synchromatic]

I was dusting out my computer with compressed air. When I put the side panel back on and booted the computer up, I noticed that there was no sound coming from the audio out in the back panel. However, the audio jack in the front worked. Any ideas on how to fix this?

 

[FAST6191]

Some more info would be nice, is your sound via the motherboard itself or via a card (probably on a very small connector) or a full blown card?

If the latter two try reseating the card as you might have tweaked it bringing it out. Also is the front panel to the motherboard or the "card", if the latter it gets interesting but if the former the it is definitely time to look at the card.