InDesign CC15 crashing on startup (Public.dll)

While working on a file, InDesign crashed. When I went to restart it, I got a Windows (7 Pro) message with the following content:

Problem signature:

  Problem Event Name:    APPCRASH

  Application Name:    InDesign.exe

  Application Version:    12.1.0.56

  Application Timestamp:    58c988ec

  Fault Module Name:    Public.dll

  Fault Module Version:    12.1.0.56

  Fault Module Timestamp:    58c9877a

  Exception Code:    c0000005

  Exception Offset:    0000000000120c52

  OS Version:    6.1.7601.2.1.0.256.48

  Locale ID:    4105

  Additional Information 1:    39e7

  Additional Information 2:    39e71e39fbd77882240b9e7d89ae06a3

  Additional Information 3:    f8a1

  Additional Information 4:    f8a1aa5c4ded473e34572ffc957c4562

I have uninstalled InDesign 15 and reinstalled. I have uninstalled 15 and updated to 17. And I have signed out of CC and signed back in. Nothing works.

Any help would be greatly appreciated!