Have you tried the following?

Right click on file icon (in explorer, for example). Then choose Open in
program - Choose initial program. Check the option: For opening this file
type always use choosen program, then push the Browse button and find your
exel application file.
N.B. My Vista is not English, I have tried to "decribe" the steps somehow,
hope it helps, in Windows XP/2000 it should work similarly.

"JoAnn" wrote:

Hello,

I can no longer double click on a file name and open it, either in Excel or
Word. When I double click a file name, what opens instead is the main
application, I then have to click open and choose the file to open.
Any suggestions as to how this can be fixed.

JoAnn