Finder settings disappear with every restart: icons rearranged, background/desktop reset, etc. Why?

OK, I followed your advice, and deleted the "com.apple.finder.plist" file (HD>Users>[user]>Preferences>com.apple.finder.plist). (After it is moved to the Trash, a new com.apple.finder.plist file auto-generates to take its place in the Preferences folder). Then I restarted.

Result? Zilch. No change.

I tried this several times in several ways: making changes to the Finder settings first, then deleting the com.apple.finder.plist file, then immediately restarting; or making no changes to the Finder settings first, then deleting the com.apple.finder.plist file and then subsequently making changes to the Finder, then restarting; etc. multiple times. In every instance, the new settings did not "take" and the Finder settings reverted to their original default status.

Any additional suggestions, since this step (which I had been very optimistic about) didn't work?

Also, some new info: The Finder window which I'm trying to change the settings for is the "Macintosh HD" top-level directory (i.e. the folder that contains the "System," "Library," "Users" and "Applications" folders) --I'm not trying to change any folder inside a "Users" folder. Not sure if this is relevant, merely mentioning it just in case.

Before I even got around to testing your suggestion, I accidentally discovered the solution, through random trial-and-error:

I highlighted the icon for the "Macintosh HD" on the desktop, pressed "Command-I" to "Get info," clicked the lock symbol at the lower right of the info pane, and THEN (here's the key) clicked on the little gear symbol that appears at the bottom center of the info pane, and chose "Apply to enclosed items..."(what was being applied was the already-extant "Read and Write" permission for the primary admin user). I don't know why this should have worked, since the problem was with the top-level hard drive directory itself, not its "enclosed items," but for whatever reason -- it worked! I made some minor Finder preference change, then restarted -- and the change remained and persisted. Finally.

So, consider this question solved.