当灰色背景图像用于页面时，组合框显示在IE6中

I am facing this queer problem: what i am trying to achieve is like on page load one pop-up would be shown where users need to do something to get the page going, a grey image background is applied to the body to keep the page inactive. But in ie6 the comboboxes of the page shows active and user can select values whish is so frustrating. Can we inactivate the comboxes with the help of css.I am facing this queer problem: what i am tryin