Fabulous fluid problem

Hello I have a very strange problem When I make changes to the site (appearance/customize) such as background colours I can see the effect immediately. If I save and publish then click visit site I can see the changes there. However, If I open a new window and go to my site I see an old version of the customization. I can make changes such as page content and they are reflected in the site but not the customization changes, Re-booting has no effect. I added some CSS to make the mane menu left aligned and the problem seems to stem from that. I have removed the CSS and the main menu is right aligned when in Wordpress administarator but left aligned when just entering the site. It is as if save and publish is having no effect. Can anyone help Regards Ed