Can you still view recorded shows on the hard drive, as well as the cable box feed thru the line input?
If so, then it's the dvd drives that have gone bad and need replacing. If you can't access the hdd or view the Line input channel, then the problem is the well documented capacitor failure, which will not power the hard drive or any other functions (you've reported the time reset itself, so that sounds like good news-maybe it's only the dvd drive/laser assembly that's failed).
If you choose to send them in to Panson's Elgin service center, you can include in your letter to them to save the contents of the hdd, and they will. Enter Panasonic Elgin IL (or Panasonic Repair) into the search box to find the address and phone number. It should be easy to find, as the problem/topic you'll dealing with comes up almost monthly.
If you're up for it, you may be able to attempt repair of them on your own. You could buy a functioning Panasonic recorder off ebay, and remove it's dvd drive to replace one in your EH55. DVD Drive swappablity (by model) is also discussed in one of the Panasonic Repair threads.
Dazed and confused over high tech.
Sigh...Concrap. The Internet Overlord Cometh
They're not com-tastic!