X7 (64bit) in Windows 10 - Crashes when you do File>Open or any other method of file opening

It ran fine for months, then a couple days ago, it began this crashing when I do "open other" on the welcome screen, or do File>Open from the menu, or click the Open File button.

Just to be clear, the crash is immediate - it is not related to a specific file - you don't get far enough to select a file.

I have tried the F8 reset, and I have uninstalled and re-installed (twice) to no avail.

Does anyone have any suggestions as to what might be the cause (and fix)?

thanks