What happened to Dell? Technical Support is a long Drawn out process with no resolution - I'm talking years

Well, I bought a laptop around 10/2009 and about 6 months later it went in for service and Tech support chose to exchange it, I can't even remember what the problem was. But I do know that I did not ask for an exchange. They told me that was the option available. The exchange came and turned out worst than the original. I need a laptop for my work which requires multimedia usage. The exchange came with a noise during any playback that I originally thought was a small problem and ignored it, until it persisted. During all playback, videos, movies, games ets. the laptop freezes while it makes a sort of grinding noise - this lasts for a few seconds and it happens throughout the playback about every 25-40 seconds. It becomes very annoying, so much so that I don't even use the laptop anymore except when I am talking to Dell. I have been contacting Dell Tech Support for help for over a about close to 2 years on and off. This past year at least 15-20 times, by phone, online chat, and Email. I've spent countless hours with Tech support to no avail. Everytime I contact them, they try something and every person I speak to try the same thing over and over; Reintstalled Windows about 10 times, they updated everything until they got to a point where they started replacing parts that same to have no connection to the problem to my non-technical eyes, such as the fan, hard drive, motherboard and then finally, the speakers. They brought the system into the Depot several times and still it came back with the same issue. I think they probably don't even do anything to the computers at the Depot, because if they did and then tested my laptop afterwards - it would have been very obvious that nothing changed. They seem to have run out of parts to replace and decided I should deal with it. Today I was told that a replacement would not be possible, even though I still have close to a year left on my additional warranty. I want what I paid for, a normal working computer. If they really check their records they would see that this laptop has been a problem from the beginning. At this point, I don't think I will ever buy another Dell anything, and i cannot recommend them to anyone either.