custom checkbox repeating in ie7 and ie8

custom checkbox repeating in ie7 and ie8

Custom check box of a form I am buidling seems to get repeated in IE7. I
am using "custom-form-elements.js" from
http://ryanfait.com/resources/custom-checkboxes-and-radio-buttons/
It is working fine except the check box seems like repeating in IE7 and
IE8. I have added the javascript file as stated there. Attached is my
check box image file
In the javascript file I have changed the width/height as below
var checkboxHeight = "24";
And in my css as below
.checkbox {
width: 25px;
height: 24px;
padding: 0 5px 0 0;
background: url(../images/checkbox.png) no-repeat;
display: block;
clear: left;
float: left;
margin-left: 90px;
margin-right: 20px;
}