Windows 2000/XP SP Reinstallation
You do NOT have to Reinstall Windows
2000 or Windows XP Service Packs after system state changes...
After you have installed the
service pack, you do not need to reinstall it if you add a device or
new software to your computer. For example, Windows 2000 and Windows
XP include a file named Driver.cab, which contains all of the files
potentially installed by Plug and Play (PnP)-class installers. Setup
and other components use this file to install the drivers for new
devices (for example, a PCMCIA card or a USB keyboard) without
requiring access to the Windows CD or the network.
The service pack does not update
the Driver.cab file itself; instead, the Update.exe program installs
an additional driver file named Sp1.cab (or other if the SP number
is greater). This file contains only updated versions of drivers
that exist in the original Windows 2000 or Windows XP Driver.cab
file. In addition to the Sp1.cab file, the Update.exe program
installs a new Drvindex.inf that points to Sp1.cab for all of the
updated drivers and also points to Driver.cab for all of the
remaining drivers.
Update.exe installs a Layout.inf
file. Layout.inf ensures that the correct software is installed and
that all the correct updates are made to Windows 2000 or XP when you
remove services from or add services to your computer. For example,
if you remove a service from Microsoft Windows NT 4.0 and then
reinstall it there, you must reinstall the service pack after you
reinstall the service. This is unnecessary in Windows XP. The
Layout.inf file is updated automatically to determine which files
must be installed from the original Windows CD or from the service
pack and, if necessary, the file prompts for the appropriate media.
When you install a Windows 2000 or XP service pack, the Update.exe
tool performs the following actions:
- The Layout.inf file is updated
with an additional source for the Windows service pack files.
When you change or add components, the Layout.inf file points to
the correct source.
- The source location is stored
in the following registry key:
- The source might be a network
share for the Windows service pack, the Windows XP/2000 service
pack CD-ROM, or if you install the service pack by using the
Express Installation feature from the Web, the
%SystemRoot%\Servicepackfiles folder.
- The Drvindex.inf file is
updated to point to an additional .cab file for drivers that are
updated in the Windows service pack. The .cab file is named Sp
n.cab (where n is the service pack version number). This file is
installed in the %SystemRoot%\Driver Cache\I386 folder.
- A new Sp n.cat file (where n
is the service pack version number) is installed for the updated
files. This file replaces any previously installed Sp n.cat file
that was installed with a Windows XP/2000 hotfix.
- The Sp n.cat file is installed
in the
%SystemRoot%\System32\CatRoot\{F750E6C3-38EE-11D1-85E5-00C04FC295EE}
folder
- Windows service packs also
perform version checking on files so that post-Windows SP n
hotfixes (where n is the service pack number) remain in place.
You do not have to reinstall
hotfixes after you install the service pack. For example, when you
install Windows XP SP1, hotfixes that you installed before you
install Windows XP SP1 are updated to the Windows XP SP1 files.
Hotfixes that you install after you install Windows XP SP1 are not
replaced.
Note that hotfixes do not update
the Layout.inf file. Therefore, if you install a hotfix and system
state changes occur, you may have to reinstall the hotfix.
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