Help with re-routing

I have read every single how-to on wordpress to get my website to come up when someone uses my main domaine.

I have my wordpress installed in a subdirectory /abc123 when i use my main domain i got a 404 (page not found) error. But, when i use xxxx.com/abc123 everything works fine. When i try to change it in the General setting of the dashboard it gives me a 404 for both the root and sub. Then i have to restore the database to get back everything.

htaccess didn’t work either. Nor did redirect through hosts cpanel.

am i missing something here?

I just am looking for a sure fire way that wont cause anymore errors and actually work.