Mine does do something similar.
boots with "Hello" or "please wait"
Hear the HDD spin up
stays on for ages
Diagnoses U80 or U81, HDD spins down
Displays that for about 10 minutes
laser in disc drive heard to move
HDD heard to spin up
unit restarts and begins cycle
I'm power cycling it again for the third or fourth time tonight.
I have heard on the AV Forums grapevine that these Panny units can be corrupted by any exposure to any electromagnetic mess, whether that be from RF or mains hash. Wifi internet, mains hash, faulty light switches, showers etc. Even neighbours' appliances.
(If that is the case, then my neighbours and Neighbours would both be the cause of me not watching TV!