Some pix to help with understanding http://www.fixyourownprinter.com/forums/laser/42093, on fixing the laser motor on this printer (didn't work for me, but there you go..). I found this HP manual very helpful for getting the top panel off (don't follow the manual beyond that, it's covering other issues).

• The two buttons for removing the rear right panel
• The clip that lets you remove the front right panel
• The clip that lets you drop the rear door down
• The rear door fully open
• The left side rear screw you need to remove
• The right side rear screw you need to remove
• The back with the rear panel removed (may not be necessary, but I found it easier)
• That pesky clip you need to remove (even peskier to replace…)
• The clip from the outside
• The front top screws (number 1)
• The front top screws (number 2)
• The rear screws securing the top (number 1)
• The rear screws securing the top (number 2)
• You also need to open the black clip on the right
• And the grey one on the left
• Now you should be able to lift the top panel off
• The top of the laser assembly
• The top removed, showing the mirror motor
• Optics that are worth cleaning
• The motor assembly removed
• The clip you need to remove to be able to open the motor assembly