Unless you have a TV with progressive scan which you can then go into the menu and change it back to off, I would suggest the following.
On all my Panasonic DVDRs(never had a EH57 though) to return the unit back to factory defaults (including off for progressive scan) you should, with the unit on, press and hold both channel up and channel down buttons on the main unit for at least 10 seconds. Doing this will not harm anything on your HDD but will return almost all setup options back to factory defaults. I'm not sure what it would do to your TVGOS(if your model had that). Otherwise it should solve your problem. Too bad Pannys didn't have the failsafe option like on Windows. As you may know in windows if you change screen resolution to something that is not visible on your screen it reverts back to previous resolution unless you highlight something that unless you can see the screen, you cannot. In this case it goes back to previous setting. Been their, done that;)