JSI Tip 7271. When you try to install a service pack on Windows XP, you receive 'Access Denied'?

The subject problem, assuming you have administrative privleges, is that you do NOT have Full Control permissions on the following registry key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update.

To fix this problem:

1. Use Regedit.exe to navigate to:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update.

2. Right-click the Auto Update sub-key and press Permissions.

3. Grant the Administrators group Full Control.