Most, if not all, of the responsive function is housed in the file css/responsive.css. The stylesheet style.css in the theme directory has very few other styles only related to theme supplied sample home page.
You can try getting the css deleted when the user clicks on a link using JS/JQuery. Or better change the CSS url from responsive.css to some other css file which has some other styles relevant to “non-responsive” site.
I must say that the theme is not built for this and hence you will face a few centring issues. You will need to remove all media queries(lines that start with @media screen and (min-width:... in responsive.css and in the style.css file and then will have to set the following value –
#container { min-width: 1180px; }