Noisy Dell laptop

My XPS1330 is making some strange noises. It sounds like a high grinding, almost squeaky noise, "electrical crackle". It sounds somewhat like a searching harddisk does, only it is fainter and a little higher. Dell came and replaced my processor. The technician said he couldn't hear the sound, but that was because he's a bit deaf himself. This did not solve my problem, so I called Dell again. Now they say they can't do anything about it and they are going to close the case. They don't give me any other option! They don't want to change any other part or give me another laptop, because the technician said in his report that he couldn't make out the sound. But I DO hear it, and so do other people. If there is background noise, I don't hear it, but when the room around me is silent (the way I like it when I'm programming), the sound really bugs me. Other laptops do not make so much noise. It ain't the harddisk, I checked. It ain't the monitor, I plugged it off. It ain't the fan, it isn't running. BUT WHAT IS IT? I'm going to call the customer service monday, and hope to persuade them to exchange my laptop for another one.