See if this is of help:
http://www.contextures.com/xlfaqApp.html#AtStartup

HTH. Best wishes Harald

"ACW" skrev i melding
...
I am trying to open Excel files - nothing fancy, just regular files - but
it
is giving me an error message that a Word document is "*.doc is not a
valid
file format.". I didn't try to open these Word docs in anything other
than
Word - why is Excel giving me this message and how do I get rid of it?