How can a end user tell if the troubles with playback of a disc is:

(a) disc related playback errors?

OR

(b) hardware errors?

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Now all three of the discs that I have had troubles with were either USED or Rental from Blockbuster.

One of the discs I could not see any form of disc damage.. the disc kept playing and it was like the old time "layer change" error.
[King Kong @ 1 hour 15mins]

The other two discs you could see small scratches which if they were DVD's would not effect playback at all?
[The Hulk @ 30mins in], [Casino @ chapters 8-10]

Are HD-DVD's more prone damage and to have playback errors with small scratches??

--David