Popping/Crackling Noise While Using YouTube.

The laptop I am using is a Dell Precision M90 running Windows 7 Professional, Service Pack 1.

The problem I'm having is that whenever I use YouTube on the laptop the audio quality of the videos has popping/crackling noise to it. I only get this problem when on YouTube, other video streaming sites are fine, and mp3 and other audio files played from the hard drive itself are fine as well.

This problem originated after I had the motherboard replaced, prior to that YouTube videos played perfectly fine. I recently had a Dell Technician to my house to repair another computer, and I mentioned the problem to him and how it originated, he told me it was a software problem, so I then re-installed my operating system and all the drivers, and the problem still persisted.

I've been trying to work through this problem in my spare time for months now, and it's to the point where it's driving me insane.

Any ideas on how to fix it?