Windows XP help: "Windows cannot open this file" error

When I try to open a file, I get a message that says 'Windows cannot open this file

What does "Windows cannot open this file" or "This file does not have a program associated with it" mean?

In Windows XP, when you see an error message that says "Windows cannot open this file", or "This file does not have a program associated with it" Windows is trying to tell you that it's not sure what to do with the file, or it does not have the software needed to view the file installed.

Every file has an extension. The file extension is the 3-letters that appear after the "Dot" in the file name. For example, a Microsoft Word file named LETTER.DOC has an extension of .DOC . It's this three letter extension that Windows uses to know what program is associated with that file; i.e., what program to open that file with.

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I can't find or do not see any 3 letter file extension!

If you don't see any 3 letter extension on your file, it is either hidden, or the file is missing the extension.

By default, Microsoft Windows XP hides extensions to make the file names more user friendly. In order to see what the file extensions are, you will have to tell Windows XP not to hide them.

    How to reveal hidden file extensions in Windows XP

  • Open Windows explorer by selecting it from the start menu, or by double clicking on the "My Computer" icon on your desktop or in the Start menu
    hide file extensions
  • Once you have your Windows Explorer (don't confuse Windows Explorer with Internet Explorer) select TOOLS, and then FOLDER OPTIONS from the menu at the top.
  • From the Windows Folder Options window, click the view tab
  • UNcheck the box that says "Hide extensions for known file types"
  • Click OK

Now you can see your Windows file extensions

Now that you can view your file extensions, locate the file on your desktop or in Windows Explorer and see what type of a file it is by looking at the 3-letter extension.
To look up file extension to see what software is required to open the file, go to

Does your computer have the necessary software?

In order to open the file, you will need the correct software installed on your PC. For example, if the file you are trying to open requires Microsoft Excel, you will either need to purchase Microsoft Excel, or download the free Microsoft Excel file viewing program from Microsoft's web site. Many software manufacturers offer free file-viewers for their software that allows you to view the file. If you want to edit or change the contents of the file, you will have to purchase the full software package.

But I already have that software installed on my computer!

It's possible that you already have the software that you need installed on your PC. If you have the correct software, but you still see the "Windows cannot open this file" error, you may have to re-associate the file type to that program.

How to create a file association in Windows XP

file association
create file association
  • From the error message that appears, click select the program from a list.
  • In the window that appears, select the correct program to open the file, and click the Always use the selected program to open this kind of file box.
  • Click OK

Windows XP will now always use the program you selected to open this kind of file.

What if there is no 3-letter file extension on the file?

It is possible that the file you have is improperly named, formatted incorrectly, or is otherwise "bad". If the file does not have a 3-letter extension it is very difficult to figure out what type of software to use to open it. The easiest thing to do may be to find the originator of the file (whoever sent it to you, or whoever created it) and ask them what type of file it is.

Links and more information:

More Technical help on file associations at Microsoft's web site: How to change file associations

More Windows help: How to in Windows XP