Windows XP Service Pack 3 Installation Errors

Microsoft has released the latest version of Windows XP SP3. It is available through Automatic updates, Windows updates and Download Center. Many users are facing an issue during the Windows XP SP3 installation process. This issue generally comes up with following error message :--
1. Service Pack 3 setup error. Access is denied.
2. Service Pack 3 setup error.Service Pack installation did not complete.
3. DoRegistryUpdates failed.

These errors can occur if permissions for one or more registry keys are restricted in a way that prevents the service pack from updating the keys. Registry keys can become restricted by certain programs that change the system access control lists (SACL) in the Registry so that administrator accounts cannot alter them. The service pack installer runs under an administrator account (User), and therefore cannot access restricted registry keys. If Windows XP Service Pack cannot update a registry key because it is restricted by another program, the service pack installation fails.

We should follow these troubleshooting methods in order to get rid off this issue :--
Method 1:--
1. We should restart the computer in "Normal Mode" and then try to download.
2. Install Windows XP SP3 from the Microsoft Download Center.
3. Restart the computer.
4. We should close or disable any antivirus or antispyware program that may be running on the computer.
5. Reset the registry and the file permissions.

Method 2:--
1. We should download and install the Subinacl.exe file.
2. Open Notepad and paste following code:
cd /d "%ProgramFiles%\Windows Resource Kits\Tools"
subinacl /subkeyreg HKEY_LOCAL_MACHINE /grant=administrators=f /grant=system=f
subinacl /subkeyreg HKEY_CURRENT_USER /grant=administrators=f /grant=system=f
subinacl /subkeyreg HKEY_CLASSES_ROOT /grant=administrators=f /grant=system=f
subinacl /subdirectories %SystemDrive% /grant=administrators=f /grant=system=f
subinacl /subdirectories %windir%\*.* /grant=administrators=f /grant=system=f
secedit /configure /cfg %windir%\inf\defltbase.inf /db defltbase.sdb /verbose
3. Save the file with name "SP3.bat".
4. Now right-click on the file and select "Run as administrator". It might take some time to complete.
5. After completion, restart your system and now you should be able to install SP3.

You should make sure that we are logged on to Windows with administrator account to complete all above methods