Thanks for the detailed suggestions.

Unfortunately, unless the panel somehow locked itself, the answer is no - it was previously working fine.  

And, of course, with the panel dead, I can't use it for any of those functions.  Can't scan, can't copy, and can't change anything.  The manual buttons DO still work, and the display shows just fine - but no touch screen input.  [Example:  If I insert a USB thumb drive, that shows up on the display and an option is to "scan to USB."  But I can't actually *do* it, because the touch screen is dead.]

[BTW, before someone asks, yes - I did unplug and re-plug power to the thing. ]  It's sort of a double whammy.  I am still on the original starter cartridges, but close enough to empty to have purchased new replacement cartridges (which now may never get used).  {:<(

jamesmknox,

Could the panel be locked? 

Panel LockThis feature prevents unauthorized personnel from changing the settings made by the administrator. For regular printing, items can be selected from the menu and printer settings remain unchanged. For regular printing, items can be configured using the printer driver.

Enabling the Panel Lock
Press the Menu Menu icon. button.
Go to Admin Settings > Secure Settings > Panel Lock > Panel Lock Control is highlighted, then press Set Set icon. button.
Press the Down icon. button until Enable is highlighted, then press Set Set icon. button.
Enter the new password, and then press Set Set icon. button.
Re-enter the password to confirm the password that you entered, and then press Set Set icon. button.
Change Password
If you change the password while Panel Lock is Enable, go to Admin Settings > Secure Settings > Panel Lock > Change Password, then perform step 4 and 5.

Reset Password
Turn off the printer. Then, while holding the Menu Menu icon. button, turn on the printer and perform steps 4 and 5 above to change the password.

Disabling the Panel Lock
Press the Information Information icon. button.
Go to Admin Settings > Secure Settings > Panel Lock > Panel Lock Control is highlighted, then press Set Set icon. button.
Select Disable.
Enter the current password, and then press Set Set icon. button to disable the panel lock.

Rest Setting
Press the Information Information icon. button.
Tap the Tools tab, and then tap Admin Settings.
Tap Maintenance.
Tap Down icon.until Reset Default appears, and then tap Reset Defaults.
Tap the desired option to reset, and then tap Initialize.
Tap Yes, Start to reboot the printer.

Dell C2665dnf Drivers, Downloads and Manuals