If IE crashes when opening an Office 2003 file in Office 2003 that has been opened and saved (in Office 2003 format) in Office 2007, install the Office Compatability Pack (avalaible here: http://www.microsoft.com/downloads/details.aspx?familyid=941b3470-3ae9-4aee-8f43-c6bb74cd1466&displaylang=en)