I need to have Excel 2003 on my machine for an occasional work around for certain older xls files. I have Office 2010 as my main office suite. I was able to just install Excel 2003 by itself (in a separate folder) and after I installed it, I had to do a repair on office 2010 for it to go back to being the default. However, my problem is this: When I open up a file with .xls extention, it opens with 2003. When I open a .xlsx file it opens with 2010. I want ALL Excel files...old version and new...to open with 2010 all the time by default. It's only occasionally where I will manually launch Excel 2003 and use the "open" command to locate an old file that I want to see in the 2003 version. How can I get Excel 2010 back to opening ALL excel files by default (.xls and .xlsx)? Window 7 seems to have lost the file associations feature that Windows XP used to have.