Audio and Video Freeze and Glitch

When playing any type of media in any program I randomly get 1 second/two second long glitch where the sound and video of the media i am watching freezes - this causes a loud buzzing sound through the speakers (presumably this is the audio stuttering in place). Then the playback goes back to normal. This can happen once every 30-45mins or sometimes longer or shorter. This problem happens whether I'm listening to just audio on the net or if I'm playing movies in any media player. My computer is an ASUS A72F-X1 Laptop Computer - Intel Core i3-370M 2.4GHz, 4GB DDR3, 320GB HDD, Blu-Ray/DVDRW, 17.3" Display, Windows 7 Home Premium 64-bit. Basically I bought this laptop purely to watch media so having the video freeze and make this horrible noise every once in a while is really annoying. I've tried updating the video drivers, changing the audio / video codecs and nothing works. Help plz!