Explorer is not on the list.
I can Browse to /WINDOWS/explorer.exe, click Open, and get it on the list
and use it to get Properties. However "Always use the selected program to
open this kind of file" is greyed out and I always have to use Browse to get
it back on the list each time I get the Open With window and want to use
Explorer.
The same thing happens when I use search, right click on an item, then left
click on "Open Containing Folder."
I can always navagate directly to something like, say, explorer.exe, right
click it, left click Properties and get the properties.
This all started when something bad happened, who knows what. I could
connect to the Internet but couldn't use any of my three web browsers,
couldn't use any of my three email programs, and found my last bunch of
System Restore Points and Image for Windows backups were unusable.