There was a problem sending the command to the program EXCEL2010 - No Fixes working

Like many others I suddenly started having an issue with anerror popping up when I try to open a .xls or.xlsx file from outside Excel. Being;

There was a problem sending the command to the program

This occurs when I double click on an excel file, but I can openit from within the excel file-open etc.

I have tried all the solutions I could find onlineincluding.

• Checking and unchecking the ignore other applications that useDDE (also doing this whilst running as administrator)
• Running the Microsoft Fix It 50392 patch (Ithink all this does is uncheck the ignore apps that use DDE)
• Ensured all boxes are unticked in compatibility
• Tried running the program as an administrator
• I have diabled ALL add-ons
• Unistalled, restarted reinstalled
• Unistalled, restarted, manually removed everyentry I could find in the registry that had excel in it (there werehundreds left after the uninstall (thanks microsoft) andreinstalled again.

I am running Win 7 ultimate.

Does anyone know what else I can try????