on a Windows XP PC. As I wrote in Windows Update: Network policy settings prevent you from using this website …, you’d often see a Windows Update error when your Corporate IT types block access on purpose.
But wait! I’m my Corporate IT type! What did I do to break it for myself???
Well somewhere along the line, I configured a system group policy to block access to Windows Update, and I ended up tripping over my own trap.
The solution/work-around was to delete the
HKEY_USERS\S-1-5-18\Software\Microsoft\Windows\CurrentVersion\Policies\WindowsUpdate - "DisableWindowsUpdate" key.
Once I did that, the Windows Update site worked with no errors.