How do I change the default zoom level in Acrobat Reader (to "Zoom to Page Level")?

Hello 

I can't get Acrobat Reader to accept any changes to its Zoom Settings!

e.g. I just want Acrobat Reader to always zoom to the "Page Level". 
But every time I change it using:
Edit ==> Preferences ==> Page Display ==> Zoom ==> Fit Page ==> OK
As soon as I close the current PDF file and view another PDF file, the setting have been changed back!

And doing  "Edit ==> Preference ==> Override Page Display ==> Always use Zoom setting ==> Fit Page ==> OK" doesn't work either. Adobe Reader forgets any changes to this too.

[This is driving me absolutely INSANE!!  WHY IS THIS SO HARD? 
It has become a deal-breaker issue for me. If I can't fix this then I shall uninstall Adobe Reader. FOREVER. ]

With thanks

J