A reader wrote to ask why she can't open some of the files she receives as email attachments. This is because she doesn't have the same programs on her computer that were used to create the recalcitrant files.

As an example, if someone sends you a text document created with Corel WordPerfect (or Microsoft Works or OpenOffice Writer) and the word processing program on your PC is Microsoft Word you will get an error message saying, "This file does not have a program associated with it."

Another example is receiving a PPS (PowerPoint Show) file when PowerPoint is not on your PC. Likewise, if you receive a PDF (Portable Document File) attachment you will need Adobe Acrobat Reader* to open it.

Well, most of the above scenarios have an easy fix available.

However, in order to use the fix you must be able to see a file name's 3-letter extension, such as ".doc" on MSWord files (MyStory.doc) or ".wpd" on WordPerfect files (MyStory.wpd) or ".wps" on documents created with Microsoft Works (MyStory.wps).
(Some files have 4-letter extensions, such as .html.)

Oddly, however, all versions of Windows have these extensions hidden by default. Here's how to unhide them:

Click on Start>Control Panel>Folder Options>View and deselect the checkbox labeled, "Hide Extensions for Known File Types." We do not want these extensions hidden!

     You can also find this option by opening any folder, such as My Computer, and clicking on Tools>Folder Options>View.

With these extensions visible we can fix most "program incompatibility" problems that may occur. Let's start with word processing documents, such as those created with MSWord or WordPerfect or with the MSWorks word processor.

If you use MSWord and receive a WordPerfect file do this:

1. Launch MSWord to create a blank page.

2. Next click on File>Open.

3. Then click the down-arrow near "Files of Type" (in the lower left corner of your blank document) and look for WordPerfect file name extensions.

4. Click the one you need, and then navigate to your WPD file using the "Look In:" box
(in the top left corner of your blank document). When you find the target file, double-click on it or click Open.

5. WordPerfect users who receive MSWord files will follow the same steps, but will look for MSWord file name extensions indicated in the "File Type" list.

     Other combinations of various word processors will have similar File>Open options.

All the above fixes involve converting an incoming file to a particular program you have. However, an outgoing file can be converted as well.

Let's say you are a WordPerfect user, but most of your contacts use MSWord (the world's most-used word processor, by the way). Before sending them a WordPerfect file, you can make it MSWord-compatible by going to File>Save As, and choosing a version of MSWord from the File Type: list.

     By the way, WordPerfect users can make their creative documents compatible with dozens of word processing programs (even some that have been obsolete for decades) while MSWord users have a comparatively short list to choose from.

Another way of making your new documents compatible with other word processors is to save them as Rich Text Format files (with the extension rtf). Windows comes with a built-in word processor called Wordpad, whose files are automatically saved as RTF documents. RTF files are normally compatible with all modern word processing programs, as well as with many that are seldom used anymore, such as Lotus Ami Pro.

MSWord and WordPerfect users will find the RTF option under File>Save As, Save as Type: or File>Save As, File Type:.

Please Note: All the above fixes work with most word processing files in most situations. However, various factors can affect conversions of various files. For instance, files created with MSWord-2007 cannot be read by earlier versions of MSWord unless the person who creates the file chooses an earlier version from the Save As: Save a Copy of the Document: options.

Another factor that can affect converting files from one word processor to another is the complexity of a document's formatting. Files with relatively simple formatting (such as those with paragraph breaks and tabs, along with bold or italic fonts) will usually end up looking like their original documents. However, files that include tables, charts, images, and various types of extra-fancy formatting may not look quite the same after being converted from one word processor to another.

Another way users of non-Microsoft office programs can open Microsoft Office documents (Such as Word, Excel, PowerPoint, or Publisher files) is to download a free "viewer" program from Microsoft. Go to www.microsoft.com and type what you need into their Search box, such as powerpoint viewer. You will then be able to download a free program that lets you read PowerPoint PPS files. However, you will not be able to create or edit PowerPoint files with the program.

*As for PDF (Portable Document Files), Adobe Acrobat Reader is a free download from www.adobe.com or www.download.com.