Outlook Express & Single File Web Pages Error

[TCM]

Recently one of our users received a new PC, which has Windows XP and Microsoft Excel 2007. Now when they try to run a Cognos ReportNet report (Cognos 8 ) in Excel format they get the error message "You need to have Microsoft Outlook Express installed to work with Single File Web Pages. Outlook Express is an optional component of Microsoft Internet Explorer 4 and later." We do not use Outlook Express in the office and this is the only user that gets this error message (everyone else can run Excel reports just fine). Anyone have any idea on what is causing this? Thank you