You can get all you want from free forum software like Wordpress which does enable you to insert a section inside your webpage and style it to match your page
(phpbb3 http://www.phpbb.com/ is a separate page with skins to choose).
All the code is downloaded and installed automatically but you then have to set up your options and forum categories via the admin; you shouldn't have to mess with the php code except once at the very beginning in a very minor way.
You will almost certainly need to install a mod or two, there are hundreds but you may have to wait for a spammer, determine what sort of spammer you have, then choose a mod to suit from advice on a forum about the mods.
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.