I am having problems with mine not playing at all. But it does make a sound like yours. I need help getting it to play. Sorry I can not help,
I have a MacBook intel 2.1GHz with 1Gb RAM running 10.6.4
Everything is working fine except that the DVD player quite frequently makes a sound as if it is trying to load a disc, this happens every few hours and when there is no disc anywhere near to it!
I have run the usual checks of permissions and an HD check with no reported errors.
Any thoughts?
Thanks

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