|File Associations in Windows 95 and 98
Introduction: Files in the Windows 95 and 98, as with most operating systems, have a type determined by the ending, for example, the ending .exe means it is an executable program and .txt is a basic text file. Many such files have "Associated" programs and, for example, when they are double clicked the associated program is run. If a .txt file is double clicked in Windows Explorer Notepad will be run and the file opened. The Associations go further and in many cases determine the menu that is displayed when you Right Click on a file name and what happens when you try to download from the internet. Try right clicking on a few different file types in Windows Explorer and notice the differences. Associations for basic file types such as .txt are initially made when the Windows 95 system is installed. Many more are made when application programs are installed and can be a major problem in installing new software, for example, almost all Word processors expect their document files to end in .doc and will set up the .doc association to be with themselves.Examining the File Associations: The file associations can be examined and edited in Windows Explorer. The menu View has at the bottom Options which brings up a screen with two tabs. The top one is labeled view and if you have not done so already you should check the button "Show all Files" and clear the box "Hide MS-DOS file extensions for file types that are registered". You will now be able to see all the files and their types. Now go to the tab called "File Types" and you will have a long list of all the file types the system understands (these may also be referred to as registered as the information is stored in the Windows Registry. If you select "Text Document" you will find that refers to .txt (and some other) files which are opened by Notepad. You can now click Edit and find a lot more information that you can BUT SHOULD NOT edit. In particular there is a list of actions at the bottom and if you highlight Open and again click edit it will show where the program is set up which is used by .txt files. Work your way back carefully using CANCELs. Installing programs: Most programs will set up associations directly in the Windows Registry. They will also be much more complex than the simple ones for .txt and Notepad we looked at as they will also use Dynamic Link Libraries (dlls), pass parameters to the program entry points and set up right click menu items. Most programs will overwrite any existing associations for file types they use - this is a major danger with Word processors which almost all use .doc and .rtf and File Viewers which can highjack associations. Some recent file viewers do check and ask what you want to do but any older ones especially those from or compatible with Windows 3.1 may not check. If the associations are highjacked you may have to reload the original program to get them back with loss of configuration and customisation. You can try noting down all the details on the file types tab and editing them back but with programs such as Microsoft Word there may be dozens of boxes.
Types of programs which may give problems: Word Processors (.doc, .rtf), Viewers (.doc), File Compression Utilities (.zip), Internet Browsers (.htm, .gif, .jpg), Graphics programs (,gif, .jpg and many others), Encoding/Decoding programs (.uue) and Virus Checkers are the prime problem areas but any applications duplicating actions of other programs can give problems. Virus checkers have to make many changes in the Registry so never load two at the same time. Internet browsers such as Internet Explorer and Netscape can coexist but one will always have to be the default browser. In the other cases problems can be expected and it is safest to uninstall one before installing another program. It is sometimes possible to keep two versions or types of word processor present but the prime (or latest) one should always be loaded last or reloaded.
OU Programs: This Technical Article was initially written with OU Students and Tutors in mind. We have experienced major problems loading Stuffit when Winzip was present which came close to a complete system rebuild - even the virus checker stopped!. An early version of the Word 6 viewer was not compatible with Word 97 and all of Office 97 had to be reloaded. We would not expect and have had no problems with FirstClass, LearningWorks, Object Shop and the M206 Course map.
Copyright © Peter and Pauline Curtis
Content revised: 2nd July, 1998