I have no sound in my computer. Went to sou...

I have no sound in my computer. Went to sound and it says No Audio Device and it's greyed out and on stop. I went into hidden devices and found a yellow bar next to PPSCAN. I had RegTool go into my computer twice and they couldn't find the problem. They said I may have a corrupt audio. I have NortonAntiVirus and Trend Spyware on all the time.Tonight I made a card for a friend and when the printer started it said Printing Started and when finished Printing Ended but I checked the computer and still no sound. Does that mean anything. Appreciate any help I can get. Thank You
Barbara