pages (cats) not styling properly

hi.
i am wondering if someone can help me.
for some reason that completely eludes me, our blog has stopped styling what seems like all pages save from the index (main) page.
when clicking on the links in the sidebar from the index page, pages load without the logo header, alignment and styling, and just generally not working.

each page should look just like the main index page, and I cant for the life of me figure out why they are not.
the rollover colours for the links are the same, which makes me think that the css file is loading, but the pages are just a mess. the sidebar is not on the right side, which is should be, and no widgets are loading either.

any help or light shed on this would be GREATLY appreciated..

please and thank you.

-m