url problem

Hello. I’m a graphic artist in trade and only know a very basic coding to set up an simple website. I have a website that’s functional (I used DW), but my client wanted to turn it into a blogsite he can update daily. So I just installed WordPress using installer of my hosting site (Hostica). It worked perfectly fine before on my first website, but this time, the only way I can view this site is if I add /wp after it’s url.

I tried:
1) removing index.html
2) copying index.php to the root directory
3) copying index.php to the rood directory and editing it
4) combination of the above
5) removing /wp from the sitename in the general page in dashboard

But whatever I do, I can’t get the wordpress site to show up with the website domain name unless I add /wp. The readers are familiar with the original domain, so I want to keep it the same, but when I type that, it either gives me the 403 error message (no index file in root directory) or leaves it blank (index.php) or gives me the original index page (index.html is present).
How can I make index.php to override the index.html???

I’d appreciate any advise. Thank you in advance.