Probably one of the most misunderstood aspects of Windows is the difference between uninstalling a program versus deleting a program. Data (documents, pictures, sound files etc), however, can be deleted safely with out affecting your computer.
In the old days of DOS (before Windows95) programs were installed on the computer’s hard drive in a very simple way. The program you were installing would typically create its very own directory and then install itself into that directory. When that program was no longer was needed, all that was necessary to get rid of that program was to delete the entire directory. Occasionally that program wrote a very simple command, during installation, in the config.sys or autoexec.bat file (theses files basically set up the computer when it booted up). When you deleted that program you would occasionally need to go into either or both of those files and delete the references to the deleted program.
Windows 95, and all subsequent Windows operating systems, took a different approach altogether. It has a file that is called the registry. The registry contains information about the all hardware that is installed on the computer, what programs are installed, a list of all files that are shared, what programs to open when a particular file is opened, etc. Also, the Windows 95 and beyond operating systems share files. Ideally, the reason for this was so that the programs that get installed would take up less disk space. Therefore, when a Windows program gets installed it creates a directory in which it installs 95 percent of its program. It then checks the shared files folder (windows/system) for the shared files that it needs and installs them if they are not there or if the file there is an older file. It then writes information into the registry about where everything is installed, what the shared files are, how to handle a specific type of file if opened, where all the shortcuts are installed, etc.
Because of all this you can begin to see the problems that can come up if you just delete a directory. If a program directory is deleted it can cause problems inside your computer. The next time the computer is started the registry is going to look for that program and give you and error stating that it can not find that program. Also when you uninstall another program, it may not delete all the files because the registry might be thinking one of the shared files is still being used even though the program it thinks is using it was deleted some time earlier.
What is the best way to uninstall a program? We suggest using the Windows uninstaller program, a third party uninstaller program, or the uninstall program that was installed with the application you are wanting to remove. A good uninstaller will not only be able to uninstall existing programs but it should be able to scan the registry for “orphan entries” (entries that refer to programs that no longer exist) and delete them as well as locate “orphan files” (files that were installed into a directory other the original program directory) and delete them. By keeping the registry clean your computer will be less like to crash and will typically run faster as well.
