fwiw I know someone else with an 8920G. His needed its dual lamp inverter replacing.
In passing he also mentioned that the Bluray device was ok to start with but had become unusable and had similar issues to yours, I googled around for a while to see what I could see and after a while concluded that the cause was, probably, upgraded
driver software or possibly firmware. tbh I cant recall exactly. He thought the player might be at fault and wanted to buy a new one.
I ran out of talent shortly afterwards, and in any event he attempted to power it up using the wrong PSU resulting in one dead laptop. Check around forums, eventually, you'll find an interminably long thread on the subject.
Go with the flow