This is a series of tutorials about working with files.

One special type of file is a program file.

Program files usually have an ".exe" extension. In contrast to, for example, text files that you create with Notepad, program files do not contain data. Instead they contain instructions to the computer. The computer executes these instructions. The instructions tell the computer what windows to put on the screen, what to do when the user enters keystrokes, and so on.

Most programs use a number of files besides the program file. These other files are often stored in the same folder as the program file. Program files are usually installed into a folder under C:\Program Files, (or D:\Program Files, etc.).

1. For example, the screenshot here shows that a program called Macromedia Dreamweaver is installed under C:\Program Files\Dreamweaver 3.
2. The actual program file is called Dreamweaver.exe. However, there are a number of other files (most of which are in subfolders) that have been installed with the program file.

Installing a program generally means:

• Copying the program file to a new folder your hard disk, usually under C:\Program Files\.
• Copying other files that the program file uses to the same folder.
• Copying some files to other folders. (For example, Screenbook Maker copies some files to your My Documents folder so that you can store new Screenbooks there).
• Registering components that need to be registered. Certain files may need to have extra information stored in a special system file called the Registry.
• Adding entries to Start > Programs, and optionally the desktop.

Because of the last three entries on the above list, you can't install a program simply by copying files to the program folder. And you can't simply remove a program by deleting the program file and the program folder. You may have to remove many other things from other locations.

Installing a program is usually done by a special program called setup.exe or a program with an ".msi" instruction. This special program copies all files to their correct locations, registers components, and adds items to the Start menu and so on. This special program is distributed by the maker of the program possibly along with other files that the setup program uses.

For an example of how such an installation program works, see the Installing Winzip tutorial earlier in this chapter.

Programs that you recieve on a CD are often configured so that the special install program will run automatically as soon as you put the CD in the CD drive.

Removing a program is somewhat different. Some programs come with an "uninstall" program that you can use to uninstall the program. Most Windows programs however, should be removed from the Add/Remove programs applet .

Click Start.

Start > Settings > Control Panel.

The control panel shows.

A list of special programs appears. These programs are called applets.

The list of applets in the Control Panel on your machine may appear differently.

The format of the list is controlled by the View pulldown . Click View.

Here View > Large Icons has been chosen. The same applets are appearing, but this time as large icons, rather than as a list with small icons.

The Add/Remove Programs applet will start if the indicated icon is double-clicked.

The Add/Remove programs applet has been started. A list of programs installed on your machine appears.

Some programs installed on your machine may not appear here, and these programs will have to be removed in a different way (either with the software maker's own remove utility, or by deleting the files in Windows Explorer. Check with the software maker for the proper removal procedure in such cases.)

Click on a program entry to select it and display information about the program. Here Acrobat Adobe 4.0 has been selected.

According to this entry, the program has been used frequently, and removing it will save 65.9 Megabytes.

Click Remove to remove the program file, all related files, menu entries, and components.

When you remove a program you may get prompted to as to whether you want to remove components of the program that are no longer used by either the program you are removing or by other programs. It is usually safe to remove all components that Windows indicates will no longer be used, because programs that share components are supposed to do so through the Windows registry. If Windows doesn't find another entry for a component in the registry, it should be safe to delete.

Windows may not be able to remove all components of an installation, in which case this information will be presented to you at the end of the uninstall.

You can select other programs in Add/Remove programs to see:

• How frequently the program has been used. Infrequently used programs might be good candidates for removal.
• How much hard disk space you will free up by removing the program.

According to the screen below, the selected program (Microsoft SQL Server 7.0) is used rarely on this machine, and deleting it would save 100 Megabytes of space on the hard disk.