Forum works in Chrome, looses BBC etc in IE and Firefox

[Wilo]

Hi,

I'm using a custom template which include our websites headers, footers, colour schemes etc.  When I access my forum using Chrome it looks fine (apart from the search being too far on the right).  When accessing the forum using IE or Firefox all the justification is lost and the menu either disappears behind the main forum space or moves to the top left.

Does anyone know what file, styling I need to edit?

Many thanks in advance,

[kat]

Got a link, so we can have a butcher's?

[Wilo]

No sorry, it's not live yet.

[kat]

Then all I can offer is some really wild guesses, so there's not much point.

I'm kinda assuming everybody else will say something similar.