Most browsers allow you to search from the address field (the place where you type the web address). Google does not do instant returns when that field is used (at least not for me).
As far as getting the Google search preferences to stick - I understand that you have tried lots of suggestions, but since I don't know what you have tried, my suggestions might be redundant: Clear out cookies and temp files (uncheck the option to save stuff for bookmarked sites)... then set your Google search preferences again.
What browser are you using?
You should have some kind of option to stop search suggestions, I am using Firefox and here's a screenshot of the search engine manager.
Jerry
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@Bongo - that would turn off search suggestions - the OP (and I) don't like Google's instant search returns. These happen when using the search field inside Google's web page. e.g. you type insta and you might see returns for instagram:
These are the settings that are not sticking for the OP - it might be a bad cookie thing.