If re-registering .dll's does not help try some of these before you consider a repair install of XP.
Automatic Updates stops working after a repair install of Windows XP
See if the Automatic Updates Service is running.
Try this workaround.
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Exp
lorer
and find the key named "NoWindowsUpdate" and delete that key. Backup (export) this key first.
You may also need to change the permissions on this branch:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate
to that of "full access"
Group Policy.
Location: Computer Configuration\Administrative Templates\Windows Components\Windows Update
Description:
Specifies whether this computer will receive security updates and other important downloads through the Windows automatic updating service.
This setting lets you specify if automatic updates are enabled on this computer. If the service is enabled, you must select one of the four options in the Group Policy Setting:
If the status is set to Disabled, any updates that are available on the Windows Update Web site must be downloaded and installed manually by going to
If the status is set to Not Configured, use of Automatic Updates is not specified at the Group Policy level. However, an administrator can still configure Automatic Updates through Control Panel.