Microsoft released qchain.exe in 2001. This utility, which works
with Windows 2000 and Windows NT, lets you chain hotfixes (i.e.,
install multiple hotfixes one after another without having to
reboot in between). In the past, chaining was difficult because
you had to install fixes in a specific order so that the update
procedure wouldn't overwrite new system files with earlier
versions. The problem with chaining was that the last hotfix
applied "won." To address that problem, Qchain manages the file-
replacement process by recording files in the registry's Pending
File Rename queue. Qchain analyzes the contents of the Pending
File Rename subkey and applies only the most current version of
the files of all applied patches.  Listing A shows sample code
that illustrates how to use Qchain in a script to deploy
hotfixes. The first three lines of the sample script apply three
hotfixes. The -z switch applies the hotfix without rebooting; -m
applies the hotfix in unattended mode, without administrative
intervention; an