It should come as no surprise that computers do a lot of things in the background. If they are irrelevant to the average user, they are unlikely to be seen. Even so, there are curious users, and it can be interesting to learn what's going on in the background.
In this article, we will discuss exactly what happens when you install a program. We've already looked at the two main methods of software distribution on Windows as well as portable software if you want more reading. For this article, we look at how Windows handles software installation.
The installation can be considered as two distinct phases. The first is to move files into the Program Files folder:these files are necessary for the operation of the software and may include plug-ins for different functions. Typically, you will need to choose the install location.
A key example would be iTunes which installs QuickTime and other Apple products alongside it. Depending on the installer, the key files can be unpacked or downloaded from the Internet.
By the time this first phase is complete, the main files and folder structure should be in the installation directory. These are all part of the properly functioning software and include all terms. You can remove some items and find a program that still works until you try some functions.
The second phase of the installation consists of modifying the Windows registry. Every program you install has an entry in the registry. Programs such as Revo Uninstaller are designed to eliminate these entries during uninstallation, removing all traces of a program from a computer.
RegShot is a program designed to take a snapshot of changes made to the registry during software installation. Using it, or an equivalent tool, allows you to observe exactly what a program is doing to ensure that it is running reliably.
If a program starts at the same time as the operating system, like Skype does, it is often written to the registry to do so. This can usually be disabled through software settings, which turns out to be a major boon for users who don't want to edit their registry.
Although it varies between installers, you could argue that the third and final phase is to give the user some control. Users can view the "readme" file associated with a program or add a shortcut to their desktop.
This third phase is questionable since it does not change anything on the computer; any user can add a shortcut to their desktop or view a readme file (many programs bundle it in the Program Files folder for easy access).
Installing the software isn't as daunting as it sounds. Although this mostly happens in the background, the actions taken make sense. The registry changes are by far the most interesting part of the installation, given how they can affect the computer.
If you're curious about the process of editing the Windows registry, it's covered tangentially in another article on disabling the timer in Microsoft Office. Again, it's not as complex as it sounds, although it's not always recommended.
