You’ll need to be able to view file extensions in Windows Explorer to follow the instructions below. If you don’t see file extensions, do the steps in Improving the view in Windows Explorer then come on back here for the rest.

 

First, start Windows Explorer (right-click Start, click Explore)
Browse to locate a file of the type you’re having problems with.

The next steps will depend on the version of Windows you have.

Windows XP/XP Home:

  • Right click on the file and select “Open With” from the pop-up menu
  • Select “Choose Program”
  • Locate the program you want Windows to use to open files of this type and select it
  • Put a checkmark next to “Always use the selected program to open this kind of file”.
  • Click OK

Other Windows versions:

  • Click on the file to select it.
  • Hold down the SHIFT key while you right-click the same file.
  • Choose Open With from the pop-up menu.
  • In the Open With dialog box, locate the program you want Windows to use to open files of this type and select it.
  • Put a checkmark next to “Always use this program to open files of this type”
  • Click OK

You can also get to the root of the problem by editing the Open action for the file association directly:

  • Use Windows Explorer to locate a PowerPoint PPT file. Click once to highlight it.
  • From the menu bar, choose Tools, Folder Options
  • In the Options dialog box, click the File Types tab
  • Scroll through the Registered File Types list to Microsoft PowerPoint Presentation and double-click it (or if using Windows 2000, click it then click Advanced in the area below).
  • In the resulting Edit File Type dialog box, double-click Open in the Actions list.
  • In the text box labeled Application used to perform action, you should see

    “X:abcdefPowerPnt.EXE” “%1”

    where X:abcdef represents the full path to the folder where PowerPnt.EXE is located. If you don’t know the exact path, use the Browse button and locate PowerPnt.EXE.
    The quote marks should be entered exactly as shown. One set of quotes around the path to PowerPnt.EXE, another set around “%1”

  • Click OK and/or Close until you’re back in Windows Explorer.
  • Now try doubleclicking the problem PowerPoint file again.

Notes:

  • You may want to perform the same steps for PPS as well as PPT files.
  • If you’re having problems with some other application’s files, substitute the appropriate file type and application names above.
  • You can also set Print and sometimes other actions here. If the Open action setting was incorrect, the others may be as well. It’s particularly important to have the %1 surrounded by quote marks.

 

Taken from a post on the PowerTools for PowerPoint PowerUsers