New Windows Update Agent 3.0 - Resolves 403 Access forbidden error
The December security updates went well on all PCs except for our family PC. After multiple attempts to update, I constantly encountered an "403 Access Forbidden error". In resolving past Windows Update issues, I almost always found solutions by searching the web based on error code or message.
The KB article below was discovered, which provides download links for the latest Windows Update software. The Windows Update Agent 3.0 replaces older DLLs and the manual download is around 6MB. After installing the latest Windows Update Agent 3.0, it resolved my "403" issues, allowing the December updates to be applied.
New Windows Update Agent 3.0 - Resolves 403 Access forbidden error
http://support.microsoft.com/kb/949104