Just had a frustrating problem, with Excel not wanting to load files when you double click on them in Explorer or from Outlook...

It turns out that Excel had set itself to ignore requests from other applications, which try and use a DDE link - not surprising since Microsoft depricated it in the mid 90s! But Explorer still uses it to open documents in MS Office!

Unchecked the ignore option and Excel documents open again in Excel 2007.

What was "funny" is, that it has worked for a couple of weeks, then suddenly stopped working yesterday, just as I needed to quickly open a documetn from my boss!