Hi quick question.
I have 4-5 mian sections to my website forum, photo gallery, classifides, personals, ect. I didnt want to use a CMS.

Is there anyway to link the users and passwords for each section? Without cms?

Sure, for the forums whatever variable shows if their logged in copy it and put it in all of your other pages.

It will be hell of a work to do without a CMS. Using CMS like joomla will save you a lot more time than any other approach you might consider. Either way you will have to convert all your pages to php first.