I've been troubleshooting this issue for the past 2 days and I can't figure out what's causing this issue.
If I try to double-click and open an excel file it will give the error "There was a problem sending the command to the program."
I have tried everything from https://support.microsoft.com/en-us/kb/3001579. I was able to get it kinda working with a registry hack that basically disables DDE. It will open but still gives the error and the registry hack will be undone with a windows or office update. This just started happening this week for us. This particular machine wasn't showing this behavior then i installed about 16 windows updates. After those were installed, it stopped working and even after removing all those updates it still isn't working.
I'm not sure what else to try at this point.