CSS z-index help in IE

I have a little problem that I cant solve.

I made a dropdown menu, and its OK but in Chrome I can only see the hover effect on the child elements, and can on the parents.

In FF and IE its OK only Chrome is the bad one, could someone give me a hint?

nav.main_menu {
            position: relative;
            top: 29px;
            left: 220px;
            bottom: 1px;
            height: 90px;
            width: 680px;
            z-index: 3000;
        }

div#container {
    width: 980px;
    margin: 0 auto;
    padding: 38px 0px;
    position: relat开发者_Go百科ive;
    z-index: 1000;
}

It's OK in any other browsers but not in IE

Are you using a CSS reset sheet. I find that solves some of my cross browser issues.

http://meyerweb.com/eric/tools/css/reset/

(you should really show your markup)