811630 Critical Update simply will not install. I am continually prompted to automatically update. I download the patch, it apparently installs but then, after a re-boot, the automatic update prompts me to apply the patch again. And so the process continues.

The same occurs if I go through windows update however it is a bit more verbose telling me that the installation failed.

This has not occured in the past and I have not made any changes to my firewall or my PC in general. Any ideas?