IE7 stops responding if a modal dialogue box is open when you try to redraw an IE7 window
A modal dialog box is open when you try to redraw a Windows Internet Explorer 7 window by using a script call in the main window. In this case, Windows Internet Explorer 7 stops responding (hangs).
To resolve this problem, install the most current cumulative security update for Internet Explorer.
A comprehensive list of IE7 related Knowledge Base articles can be found here: