I have both Office 2003 and Office 2007 installed. I can use either or with no problems. But if I click on a file it will always open it with Office 2003. I have Office 2007 setup to run in Compatability Mode and always save the files in the .xls format. The only way I can open a file in Office 2007 is to go through the program and not just by double clicking the file. I have tried to change the Open With in the properties of the files but it changes back to Office 2003 after I set it to Office 2007. Any Ideas on how to make it always use Office 2007 as my default.