I am having a hard time figuring out why the inner pages of my website are not centered when viewed in IE (IE10 is fine, the older versions are giving me the problem.) Although the home page is centered, it ignores the

margin:0 auto;

on the inner pages.
This is the link:www.chailifeline.org/events/auction/index.php

It seems that you may have forgotten to include the doctype decleration for some of your pages.

The doctype is still important specifically for IE. When there is no doctype declared, IE goes into quirks mode.

You need to simply add the doctype.. It looks like from the link you posted above you are using XHTML 1.0 Transitional as your doctype. You should consider using the HTML5 doctype on your new projets. declarling a doctype of HTML5 doesnt mean you have to include HTML5 elements right away..

The HTML5 doctype is easier to use because its simple...

<!DOCTYPE html>