double click on an Excel file, you get an error message that the file is not a valid Win32

The problem I am having with Excel 2007 on the Acer computer running Windows 7 Home Premium 64 bit, is that when you double click on an Excel file, you get an error message that the file is not a valid Win32 application. I can only open the file if I first open Excel and then click on Open and find the file, then click on it while inside the Excel program.

Sounds like a file association problem.

Try here
http://support.microsoft.com/kb/2464297
or here
http://www.sevenforums.com/microsoft...t-opening.html