main address doesnt work

Your site needs to be configured so that index.php is a default document.

how do i do that??

is is throw the wordpress interface?

and beside that my pages dont work as well ..

No, it isn’t through the WP interface. I don’t know what sort of hosting you have, but you could try adding this to your .htaccess file:
DirectoryIndex index.php

If you don’t have an .htaccess file, or aren’t sure what that is, then you’re best option might be to contact your host.

hi, i have found .htaccess file and added C:\Inetpub\vhosts\friends-poker.com\httpdocs index.php . plus i have defined the index.php as the first default file for that site.
still nothing.
i should state that none of my other pages work.

Your site is running on IIS. .htaccess isn’t going to do you any good. Chances are you are going to have to contact your host. There might be a web.config setting that you can edit but I’m not sure.

i did contact my host. they are useless.
but i have another site on my server that runs phpbb and it has an index.php as his defualt page and the site runs fine.

but i have another site on my server that runs phpbb and it has an index.php as his defualt page and the site runs fine.

Are you sure it is on the same server? Not just hosted by the same people? If it is on the same server look around for a web.config and see what it contains.