Did you exchange it and try the new laptop? You claim it's not a hardware issue but not one laptop at home or office does this so I'm thinking it's a bum laptop.
Recently purchased a new laptop, runs on windows 8.
Sometimes when i watch a youtube video for example, this problem is not limited to just youtube videos, the video will load the first frame but not play i can skip ahead but it will just load that one frame and not play. Other times the video play but no sound along with it. Note that when the video plays but the sound doesnt the audio mixer at the bottom right doesnt show that sound is playing so its not a hardware issue. Sometimes how ever the video will load completely fine and the sound will play. opening and closing the browser usually works but can take up to 10 times before the video plays with sounds or sometimes i just give up. Note I have tried to play videos on multiple browsers and the problem persists.
Any advice would be greatly appreciated, feel free to ask question if i havent provided enough information on the problem thank you.

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