Sound Card Question.?

I recently (within the past 6-8 months) purchased an Acer computer with the "media" package installed. This week, on every video, music or "sound" the computer makes, it sounds like the computer is on helium. Not so much sped up and unrecognizable, but just very high pitched and annoying. Could my sound card be going out already? I've run antivirus and spy sweeper and they both found nothing. Thank you in advance for any help.