Hi dear I am so sorry but It's wrong because the div.u_right stay at right of the parent. for this markup you need this code

.u_right{ float:left; }
.u_left {float:left}

but I rather use another code for first markup (problem markup):

.u_right
{
display:inline;
}

Hi dear you can let div#useicon stay block level but you must change a to block level and then float the div#useicon for gain width and height. and that work in all IE versions. here the css code:

a
{
display:block;
width:16px;
height:16px;
overflow:hidden;
}
div#useicon
{
width:16px;
height:16px;
float:left;
}

I used overflow for get arount collapse height because of floating div#useicon.