If you are struggling with absolute positioning a div in IE7 Or any other element, simpy add div {zoom: 1} (or replace with the elelement you are targetting) on top of your CSS. Will generally sort out your issue...
div {zoom:1} assigns a "layout" to the div. More in depth info can be found here.
div {zoom:1} assigns a "layout" to the div. More in depth info can be found here.