In Internet Explorer 7, the first time I visit a Stack Exchange site I've never logged into, the small StackExchange logo at the top of the page is a clickable link. But if I refresh the page, only the bottom row or two of pixels of the Stack Exchange logo is a clickable link. The rest of the logo results in an arrow mouse pointer and does nothing when you click.
A possible solution for this problem: In the style sheet all.css, in the item #notify-container, add
height: 0; .
Currently, in the style sheet all.css, #notify-container has a width of 100% but no height specified. For this element, when the width is specified but not the height, Internet Explorer 7 seems to set the height to about one line of text. This causes the notify-container div to cover most of the StackExchange logo and prevent all but the bottom row or two of pixles from being a clickable link. (The notify-container div also seems to cover the other links on the top right of the page, but they remain clickable, I'm not sure why.)