When any software update is installed, a backup directory is created at %SystemRoot%\$NtUninstall [KBArticleNumber] $\ for simple updates. A backup directory is created at %SystemRoot%\$NtUninstallie7$ for Internet Explorer 7
The backup directory contains the original files that the software update replaced, a file called Spuninst.exe that performs the removal, and Spuninst.inf, which contains the logic needed for the removal, including
files to be replaced and registry entries to be changed
Note: By default the backup directories are hidden. The “Show Hidden Files and Folders” option must be selected in order for you to view these directories and their contents.
Removal of a IE 7 replaces the files on the computer with the original files from the backup directory and changes registry entries back to the values they held before the software update was applied. Entries from Add or Remove Programs in Control Panel are also removed.
The following figure illustrates this process:
Load configuration file (Spuninst.inf):
This configuration file spuninst.inf has the uninstallation information
.The first step in the uninstallation process is to load this file and
execute the instructions in this file .
The uninstallation process involves in replacing the system files to the original versions and removing the files that are added during the installation process.
Restores Registry entries:
The next work of the uninstallation process is to restore the registry entries that were altered during the installation process
Performing Book keeping and cleanup:
Here the uninstallation process creates a log file of all the activities that took place during the uninstallation process which is located at %windir%\