The disc drive on my Xbox 360 is having problems?

I just bought the new expansion for Fallout 3 and downloaded it and stuff but when i go to play it after about 5 mins of play time the disc drive on my xbox starts making a sounds like the disc is speeding up and then stoping and slowing back down.kinda like its imitating a fire truck?? i dont know really how else to discribe it but after about of min of that (if im lucky) it will either freeze the game or come up with a screen telling me that my disc is dirty (which is wrong its in perfect condition) so does anybody else know anything about this problem?? ive tried emailing the microsoft support and they gave me the bull crap answer, Make sure your disc is actually clean etc,

It could be the drive
go out and buy a laser lens cleaner and try that
if not you may need to replace it

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