“The command cannot be performed” error message when you double-click to open a document in Word 2007 or in Word 2003

Method 1: Open in Word

To open the document directly in Word, follow these steps.

Word 2007

1. Start Word 2007.
2. Click the Microsoft Office Button, and then click Open.
3. In the Open dialog box, click the document that you want, and then click Open.

Word 2003

1. Start Word 2003.
2. On the File menu, click Open.
3. In the Open dialog box, select the document that you want, and then click Open.

Method 2: Remove the Template from Your Startup Folder

To remove a template from your startup folder, follow these steps. 
Word 2007

1. Exit Word 2007.
2. Click Start, point to Programs, point to Accessories, and then click Windows Explorer.
3. Locate one of the following folders:
   • C:\Documents and Settings\username\Application Data\Microsoft\Word\STARTUP
     
     Note In Windows Vista, locate the folder C:\Users\username\AppData\Roaming\Microsoft\Word\STARTUP
   • C:\Program Files\Microsoft Office\OFFICE12\STARTUP
4. Double-click the Startup folder to open it.
5. In the right Windows Explorer pane, click to select the template that you want to remove, and then press DELETE.

Word 2003

1. Quit Word 2003.
2. Click Start, point to Programs, point to Accessories, and then click Windows Explorer.
3. Locate one of the following folders:
   • C:\Documents and Settings\username\Application Data\Microsoft\Word\Startup
     
     Note In Windows Vista, locate the folder C:\Users\username\AppData\Roaming\Microsoft\Word\STARTUP
   • C:\Program Files\Microsoft Office\Office11\Startup folder
4. Double-click the Startup folder to open it.
5. In the right Windows Explorer pane, click to select the template that you want to remove, and then press the DELETE key.

Cr. https://support.microsoft.com