Have Win XP SP3 and Office 2003 with upgrade to allow it to read or save in Office 2007 format (.xml). Worked fine for awhile and shortcuts to files would open file in correct app, i.e. a word processing file would open in Word, and a spreadsheet would open in Excel, etc.

Then do not recall changing any settings, but double clicking on a file would try to open the .xml file in Internet Explorer instead of in the correct app. Obviously it does not work. What happened? What changed? How do I get it back to working properly?

The file association has changed.
Right-click the file, select "Open With", choose program.
Check the "Always use..." box.

commented: That was easy, and it worked! Right on. +1

check the following:

1. file associations
2. Target/ File Target
3. If nothing works, delete the shortcut, and then create a new short cut from the original program.

IE grabbed the file types when it upgraded.

This is one reason I do not like IE.

I don't like IE either, and only use it when it is required. I've corrected the file type issue, but I still have a question. You see, after the upgrade of Office was installed it would open worddocument.xml in Word and it would open spreadsheet.xml in Excel. How did it know to do this, since they both have filteype .xml? More importantly, how can I fix it?

probably because they were made with there prospective programs .just guessing