Excel opens, but the file doesn't

This problem sprang up out of nowhere on my XP laptop. All of a sudden, double-clicking an Excel document would open Excel, but not the file. It did not matter if the file was local or remote, if I accessed it via Explorer or not, or if another program (mail client, for instance) tried to call the file open command. Either way, I would be greeted with an empty Excel workbook. If I then chose File, Open, and browsed to my document it would then open it. Very frustrating, but I lived with it . . . until today . . .

I tracked down the problem to the file type associations in Windows XP. The resolution was quite simple once I knew what to do.

• First, open any folder in Windows XP.
• Click on the Tools menu, and choose Folder Options.   
• From the dialog that pops up, click the File Types tab. You will now be presented with a list of all document types recognized by your computer. 
• Scroll down to XLS, select it, and click the Advanced button. Now you'll see several "Actions" registered for Excel worksheets

                                                      

• Usually, Open is the default (indicated by being in bold). Select "Open" and click the Edit button.

• The main piece of data in here is the field labeled "Application used to perform action". This should point to your Excel executable, followed by some command-line arguments. Here's how it appears on my PC: "C:\Program Files\Microsoft Office\Office\EXCEL.EXE" /e "%1"
• It is very important to make sure that the %1 is surrounded by quotes. %1 is the variable representing the full path and file name of the document you are opening. If it contains any spaces, and this is not surrounded by quotes you will get a flurry of weird errors.
• "Use DDE" is normally checked. Now, make sure that "DDE Message" is empty. Click OK.
• Click OK back at the Edit File Type dialog. Click Close on the Folder Options dialog.

That should fix the problem. In my case, there was a malformed DDE Message in these properties. I have no idea how it got there, or what it should have been, but it works fine with it empty.