sub menu disappears (mainly on chrome)

I’m having trouble with my site .
The problem is that sub menues disappear before I have a chance to click them.
I’ve found similar questions here, tried to implement the answers, but had no success.

Here’s the CSS:

/************************************************
*	Navbar  									*
************************************************/
#navbar {
	background: #FFFFFF url(images/nav_orange.jpg) repeat scroll top center;
	width: 960px;
	height: 30px;
	margin: 0px auto 0px;
	padding: 0px;
	overflow: hidden;
	}

#nav {
	margin: 0px 5px;
	padding: 0px;
	list-style: none;
	}

#nav ul {
margin: 0px;
	padding: 0px;
	list-style: none;
        text-align: right;
	background: url(images/nav_orange.jpg) repeat scroll top center;
}
#nav a {
	color: #FFFFFF;
	display: block;
    font-weight: bold;
    font-size: 13px;
    margin: 0px 0 0 1px;
	padding: 8px 10px 8px 10px;
	text-decoration: none;
	}
#nav a:hover {
	background: #EFEFEF;
	color: #EE7B3C;
	display: block;
	text-decoration: none;
    margin: 0px 0 0 1px;
	padding: 8px 10px 8px 10px;
	}
#nav li {
	float: right;
	margin: 0px 0px 5px 0;
	padding: 0px;
background: url(images/sep.jpg) no-repeat scroll left center;
	}

#nav li li {
	float: left;
	/*margin: 0px;*/
	padding: 0px;
	width: 140px;
	}

#nav li li a, #nav li li a:link, #nav li li a:visited {
	background: #FFFFFF url(images/nav_orange.jpg) repeat scroll top center;/*#000000;*/
	color: #FFFFFF;
	width: 140px;
	float: none;
	padding: 8px 10px 8px 10px;
	text-decoration: none;
	z-index:100;
	}
#nav li li a:hover, #nav li li a:active {
	background: #EFEFEF; /* #2D5F6F; */
	color: #EE7B3C; /* #FFFFFF; */
	padding: 8px 10px 8px 10px;
	z-index:100;
	}
#nav li ul {
	position: absolute;
	width: 10em;
	z-index:100;
	left: -999em;
	}
#nav li:hover ul {
	left: auto;
	display: block;
	z-index:100;
	}
#nav li:hover ul, #nav li.sfhover ul {
	left: auto;
	}