cannot open excel files

Well, this one stumped me for awhile. I now have Win7 and Office 2007. All was going well, when I couldn't open any excel files. The error was:

"There was a problem sending the command to the program"

After digging around a bit, I found the solution.

Bring up the Excel options, go to advanced and then scroll down to the

"General" section. Make sure that "Ignore other applications that use

Dynamic Data Exchange (DDE)" is not checked.

I am not sure what DDE does, but after unchecking that box, I could open Excel files again.