IE 8 not showing embedded workbooks (XLS)

Hi folks.

We need to continue to use IE8 on some desktops (don't ask!) on our desktops. Users who use IE8 have noticed that embedded workbooks are not shown. They are shown in Firefox (for example), so it appears to be an IE setting, but I'm not sure what setting.

Here is an example page:

http://office.microsoft.com/client/helppreview14.aspx?AssetId=HP010342586&lcid=2057&NS=EXCEL&Version=14&tl=2&respos=0&CTT=1&queryid=ed0afd65-6983-4d9b-98cb-260bee6a4d5c

When this is viewed in IE8, on our desktops, the embedded XLS workbook is not shown at all - there is just a blank area (you don't get the ExcelWebApp ribbon at the bottom either). If I view the source, there are only HTML tags with nothing between them.

Can anyone suggest any ideas on how to get the workbook showing?

Users are administrators, UAC is switched off, Windows 7 32 bit.