IE dropping a nav button

Hello. I cannot figure out why IE 6 & 7 are dropping the view cart button on this page:
[url]http://www.barkleigh.com/store/pc/home.asp[/url]

The only way I have figured out on how to make it not drop is to resize the header image to 850px and no bigger. Why does that work, I don’t know. I am frustrated to the max on this issue! Please let me know your thoughts. Thanks a bunch

Also in #CSS _↴