Windows 7: Quickbooks iif files cannot change default program

I had no problem before I installed Office 2007. But now I cannot change the default to open the file. Actually it is a tab delimiter text file and to view it I have always opened it with excel. I was created with excel and saved as a tab delimiter text file, but with the extension iif.

I go an select the default program to be Excel.exe, but it just does not take it. the first time I tried to associate, it came up with 2007 microsoft office component and excel is not on the list of possible programs. Trying to open the file with 2007 office componen fails, with the error message that it is not a valid Win32 application.

If I open excel and then use file open, the file opens just fine. I probably need to change it in the registry, but I would not know where to look and what to change.