I am a teacher who uses 2003 since that is what is on the school network,
(and I personally prefer).
I sometimes have students who need to use 2007 so that , for example, they
can print/demonstrate the new conditional formatting.
I have a copy of 2007 enterprise on my laptop (for onenote and outlook) but
every time that I install excel 2007 it grabs the xls files for its own! I
have tried installing 2003 after 2007 and this seems to work ... for a while,
but when I run outlook office seems to 'repair' itself and xls is back to
2007.

How can I have both versions on my laptop but have the default be 2003?

Thanks.