Here's how I got my audio to work again in my Toshiba Satellite laptop.
Put the laptop to sleep ( Wait till lights go out. The power icon should glow orange.)
Hit any key to wake up the machine and log back in.
Immediately start moving the volume scroll wheel back and forth until the red cross on your taskbar's audio icon disappears.
As your computer awakens from sleep mode, it will try to re-establish communication with its hardware; this is when your computer should detect the communication activity being sent by the audio device as a result of you manually moving the volume scroll wheel.