This article applies to you if your computer uses the Windows operating system (any version) and when you double-click on a file or an e-mail attachment:

• You get an error message like, "Windows can't open this file";
• The file opens, but it is unreadable -- doesn't look the way it should.
• The file opens and is readable, but the program that opens isn't the one you want.

The basic thing to know about this type of problem is that when you double-click on a file, Windows uses the file extension to determine which program to use to open the file. The file extension is the part of the file name that is at the end, after a period.

So, your problem is most likely caused by one of these things:

• The file you are trying to open is missing a file extension;
• The file you are trying to open has a file extension that refers to a program you do not have installed on your computer.
• Windows associates the file extension for your file with the "wrong" program.

To resolve any of these problems, you will need to know which file extensions go with which programs. The file extensions most commonly used by retirees are:

• doc = Microsoft Word, versions older than Microsoft Office 2007
• docx = Microsoft Word, versions starting with Microsoft Office 2007
• pdf = Adobe Reader, all versions. Several other programs will open this format also -- it stands for "Portable Document Format".
• jpg, jpeg, gif, tiff, png - These are images, which may come from scanners, cameras, downloads from photo sites, etc. There are many programs that can open these correctly. The default in Windows is normally Windows Photo Viewer, which is part of Windows itself.

You can find lists of file extensions and what they associate with on the Internet. One example is from FileInfo.com.

 Missing File Extension

If your file name does not end in a period and some letters, Windows does not know what program to use to open it. Be aware that by default Windows hides file extensions, so the extension might be there and you're just not seeing it. It is easy to change this, so that you can see the extension.

If you know the program that should open it and you know that you have that program installed, you can:

• Right-click on the file name and select the program you want from the list that you'll see; or
• Rename your file, adding ".xxxx" to the end, where ".xxxx" is the extension for the right program.

If you don't know what program should open the file, you may have to ask the person who sent it to you. Note: Files sent out to the ASURA Board of Directors for use in Board meetings are almost always PDF files, i.e., the file names end, or should end, in ".pdf".

 Extension is for a Program You Don't Have Installed

If you don't have a program installed that works with the extension on the file you are opening, you won't be able to open the file.

The solution is to either:

• Install a program that will open the file. This is practical when there are free programs to open them, such as Adobe Reader to open .pdf files.
• Ask the person who sent you the file to send it to you in a different format, which can be read by a program you DO have installed. This is usually practical for something like a Word document that was created by a later version of Word than you have installed -- the sender can use the "save as" function of Word to create a "doc" version instead of the default "docx".

 Windows Associates The Extension With the "Wrong" Program

Sometimes, "things happen" that cause Windows to associate a particular file extension with a program that isn't the one you want. If you know what program you do want, it is easy to fix this.

To get instructions:

• Type "Change the program that opens a type of file" in Windows help on your computer; or
• Use your browser's search function (e.g. Google) to find instructions by typing, "Change the program that opens a type of file xxxxxx", where xxxxxx is the version of Windows that you have, e.g. Windows XP, Vista, Windows 7.