Header Mouseover from Dreamweaver Javascript to CSS

My site suddenly started loading slow only on IE and I believe I traced it to the javascript in my Header that controls the rollovers on the buttons. It is old Dreamweaver 2004 bloated javascript with deprecated arguments. I would like to change it to CSS I could most likely complete this but am short on time to work on it. I would supply the script currently being used,and the images folder. Also the site so you could look at it. Works fine in FF and Chrome and Opera. Just lags recently in IE. This should be fairly simple and could eliminate one possibility of the sudden lag in IE.