Why can't I open a file with .docx as the extension?

If the version of Word you have is prior to 2007 and the "additional program" was the Microsoft Compatibility Pack, then Word should be able to read .docx documents.

However, it may not automatically open when you double-click one. Try this:

In Windows XP:

1. In Windows Explorer, find a .docx file.

2. Right-click on it and select Open With.

3. If MS Word shows up, select it.

4. If it does not, click the Browse button. Navigate to the directory C:\Program Files\Microsoft Office\Office10 (Office10 for Word 2002 (XP), Office11 for Word 2003). Find and select the file winword.exe.

5. In either case, check the checkbox Always use the selected program to open this kind of file.

6. Click OK.

In Windows Vista:

1. In Windows Explorer, find a .docx file.

2. Right-click on it and select Open With. If a menu pops up, select Choose Default Program.

3. Go to Step 3, above.

Hope that helps.

Download the compatibility pack for Office. .docx files are created with Word 2007 and it looks like you have something earlier.

http://www.microsoft.com/downloads/details.aspx?Fa...

If the file is missing an icon/thumbnail/tile...etc, you may need to associate the .docx file with Word.