Without claiming any degree of technical insights... a system has a certain
array of icons which fall into two general categories: those specific to the
programs installed on that system and generic icons provided by the OS.
If the icon associated with the type of file is available when the file
shows up that's the icon which will be displayed. If not, one of the generic
icons will be used. IOW, if you had no versions of Word installed some other
icon would be associated with that file type. Installing a Word version then
makes the associated icon available so that's what would be used in place of
what had been used previously as a "substitute".
If you don't like the default associations you can right-click a file (among
other options) & change the association for files of that type -
individually or universally. Specifics vary depending on Window version, but
it's actually Windows, not the programs or "other people", that determines
what icon to use for what types of files.
Regards |:>)
Bob Jones
[MVP] Office:Mac