No Access to Settings Tab

Hi People,
I installed OC and everything was fine for a couple of weeks now I logged in and got a json message (can't remember what it said) instead of dashboard, refreshed page and dasboard loaded. I now have no 'dropdown' button on settings tab and when clicked it goes startiaght to stores.
I uninstalled, created new database and swapped version 4.0 for version 3.0.38 and still no access to the settings.
Any ideas would be appreciated.
Bob

What do you mean by "'dropdown' button on settings tab? How does you menu differ from the demo (https://www.opencart.com/index.php?route=cms/demo)?

Your description so vague that nobody will be able to understand you.

If you really want help, you need to provide more details, and a clearer description.